energies
Article Steam and Oxyhydrogen Addition Influence on Energy Usage by Range Extender—Battery Electric Vehicles
Andrzej Łebkowski Department of Ship Automation, Gdynia Maritime University, Poland Morska St. 83, 81-225 Gdynia, Poland; [email protected]
Received: 26 August 2018; Accepted: 10 September 2018; Published: 11 September 2018 Abstract: The objective of this paper is to illustrate the benefits of the influence of the steam and oxyhydrogen gas (HHO) on the composition of emitted exhaust gases and energy usage of operating the internal combustion engine (ICE) that drives a generator-powered battery electric vehicle (BEV). The employed internal combustion generating sets can be used as trailer mounted electric energy sources allowing one to increase the range of BEV vehicles, mainly during long distance travel between cities. The basic configurations of hybrid and electric propulsion systems used in a given Electric Vehicles (xEV) includes all types of Hybrid Electric Vehicles (xHEV) and Battery Electric Vehicles (xBEV), which are discussed. Using the data collected during traction tests in real road traffic (an electric car with a trailer range extender (RE) fitted with ICE generators (5 kW petrol, 6.5 kW diesel), a mathematical model was developed in the Modelica package. The elaborated mathematical model takes into account the dynamic loads acting on the set of vehicles in motion and the electric drive system assisted by the work of RE. Conducted tests with steam and HHO additives for ICE have shown reduced (5–10%) fuel consumption and emissions (3–19%) of harmful gases into the atmosphere.
Keywords: electric vehicles; range extender; battery electric vehicle; hybrid electric vehicle
1. Introduction Recent rapid intensification of climate change has motivated governments to discuss the possibility of introducing renewable energy sources in the transport sector. One of the theories claims that greenhouse gases emitted largely by transport are responsible for global warming and smog in cities [1]. On this basis, far-reaching steps have been taken to limit the emission of toxic substances by vehicles used in road transport [2]. These activities are aimed at the development of vehicles powered by electricity. However, the limitations of electric energy storage systems cause such vehicles have a relatively short range and the charging time is rather long—it typically ranges from several minutes to hours. To address these disadvantages, several different approaches were proposed to use various types of technological solutions, such as assembly of overhead traction lines supplying vehicles over the road on which they are moving [3] or construction of roads with a layer of photovoltaic panels with devices for wirelessly transferring energy directly to the vehicles [4]. Other proposals involve the use of electric drive systems [5–10] supported by an internal combustion engine (ICE) (a hybrid electric vehicle or HEV) [11], fuel cells (fuel cell electric vehicles or FCEVs) [12,13], supercapacitors [14], hydraulic [15] or pneumatic systems, as well as various types of electric batteries [16] with the possibility of charging them (plug-in hybrid electric vehicles or PHEVs) (Figure1). The purpose of these technologies is to increase the range of vehicles while simultaneously minimizing greenhouse gas emissions. The impact analysis of using hybrid electric-combustion drive systems on the pollutants emitted by the vehicle has been presented in [17–19].
Energies 2018, 11, 2403; doi:10.3390/en11092403 www.mdpi.com/journal/energies Energies 2018, 11, x FOR PEER REVIEW 2 of 20 minimizingEnergies 2018 greenhouse, 11, x FOR PEER gas REVIEW emissions. The impact analysis of using hybrid electric–combustion2 of 20 drive systems on the pollutants emitted by the vehicle has been presented in [17–19]. Energiesminimizing2018, 11, 2403 greenhouse gas emissions. The impact analysis of using hybrid electric–combustion drive2 of 20 systems on the pollutants emitted by the vehicle has been presented in [17–19]. PE PE SUPERCAPACITORS SUPERCAPACITORS SUPERCAPACITORS SUPERCAPACITORS
FigureFigure 1. Sample 1. Sample configurationsconfigurations configurations of of hybrid hybrid drivedrive systems: ( a( a) )serial serial hybrid hybrid drive, drive, (b) (parallelb) parallelparallel hybrid hybridhybrid drive,drive, ( (cc)) parallel parallel(c) parallel hybrid hybrid hybrid drive, drive, drive, (d ( )d serial)) serial serial hybrid hybrid hybrid drive drive withwith with fuel fuel cell, fuel cell, (e cell, )( eparallel) parallel (e) parallelhybrid hybrid drive hybrid drive with drive with withhydraulichydraulic hydraulic motor, motor, motor, (f) hybrid(f) (hybridf) hybrid drive drive system drive system system with with motorsmotors with motors anandd converters converters and converters mounted mounted in mounted ain wheel; a wheel; inBATT– a BATT– wheel; BATT—BatteryBatteryBattery Pack; Pack; EM–Electric Pack; EM–Electric EM—Electric Motor; Motor; HM–Hydraulic Motor; HM–Hydraulic HM—Hydraulic Motor; ICE–Internal ICE–Internal Motor; ICE—Internal Combustion Combustion CombustionEngine; Engine; FT–Fuel FT–Fuel Engine; Tank; HT–Hydrogen Tank; HPT–High Pressure Tank, FC–Fuel Cell; G–Generator; PE–Power FT—FuelTank; HT–Hydrogen Tank; HT—Hydrogen Tank; HPT–High Tank; HPT—High Pressure Tank, Pressure FC–Fuel Tank, Cell; FC—Fuel G–Generator; Cell; G—Generator; PE–Power Electronics; iWEM–In Wheel Electric Motor; T–Transmission. PE—PowerElectronics; Electronics;iWEM–In Wheel iWEM—In Electric Wheel Motor; Electric T–Transmission. Motor; T—Transmission. The ideal car should be emission–free, quiet, environmentally friendly, with a driving range of The ideal car should be emission-free,emission–free, quiet,quiet, environmentally friendly, with a driving range of around 1000 km (620 miles) and inexpensive in daily operation. Most of these requirements could be around 1000 km (620 miles) and inexpensive in daily operation. Most of these requirements could be aroundmet 1000 by various km (620 electric miles) vehicle and inexpensiveconfigurations in (Fig dailyure 2),operation. however Mostobstacles of these are caused requirements by the current could be met byenergy various storage electric devices. vehicle configurations configurations (Figure(Figure2 2),), howeverhowever obstaclesobstacles areare causedcaused byby thethe currentcurrent energy storage devices.
Figure 2. Sample configurations of xEV drive systems: (a) classic drive system, (b) drive system with supercapacitors, (c) drive system with four independently operating motors and converters mounted on the vehicle body, (d) drive system with independently operating engines mounted in wheels and Figure 2. Sample configurations configurations of xEV drive systems: ( a) classic drive system, (b) drive system with converters mounted on the vehicle body, (e) drive system with independently operating motors and supercapacitors, (c) drive system with four independently operating motors and converters mounted supercapacitors,converters mounted (c) drive in systemwheels, (withf) drive four system independently with independently operating operating motors motors and converters and converters mounted on themounted vehicle in body, wheels, ((dd) )superc drivedriveapacitors systemsystem withwithand fuel independentlyindependently cell. operatingoperating engines mounted in wheels and converters mounted on the vehicle body, ((ee)) drivedrive systemsystem withwith independentlyindependently operating motors and convertersThe list mounted of shortcomings in wheels, is (long,f) drive and system includes with lo independentlyw energy density operating in comparison motors andto liquid converters fuels, mountedlimits on incharging/discharging wheels, supercapacitorssupercapacitors current and values fuel cell.cell. (power density), limited power available from the public electrical distribution grid (available connection power, connection capacity to receive energy The list of shortcomings is long, and includes low energy density in comparison to liquid fuels, Thefor bi–directionallist of shortcomings chargers is long,mounted and onincludes the vehicle) low energy [20,21], density and infinally, comparison limited tooperating liquid fuels, limits on charging/discharging current values (power density), limited power available from the limitstemperature. on charging/discharging The solution could current be to develop values batteri (poweres withdensity), very high limited energy power density available of up to 1–1.5from the publickWh/kg, electrical or employ distribution a miniature grid (availablenuclear reactors connection operating, power, for example, connection on a thorium–uranium capacity to receive cycle energy public electrical distribution grid (available connection power, connection capacity to receive energy for bi-directional chargers mounted on the vehicle) [20,21], and finally, limited operating temperature. for bi–directional chargers mounted on the vehicle) [20,21], and finally, limited operating The solution could be to develop batteries with very high energy density of up to 1–1.5 kWh/kg, temperature. The solution could be to develop batteries with very high energy density of up to 1–1.5 orkWh/kg, employ or a employ miniature a miniature nuclear reactors nuclear operating, reactors operating, for example, for on example, a thorium-uranium on a thorium–uranium cycle (Th-U) cycle [22]. Unfortunately, neither technology is yet available and therefore alternative solutions are desired. The use of an additional source of electricity on the vehicle or attached trailer can be a solution to this issue. One of the first technologies that was commercially introduced to increase coverage and Energies 2018, 11, 2403 3 of 20 Energies 2018, 11, x FOR PEER REVIEW 3 of 20 reduce(Th–U) CO2 [22].emissions Unfortunately, at thesame neithe timer technology was the is hybridyet available drive and (HEV) therefore technique, alternative in serialsolutions or are parallel configurationdesired. The (Figure use of1), an combining additional thesource capabilities of electricity of the on ICEthe vehicle and the or electric attached motor. trailer Thiscan be concept a assumedsolution the to placement this issue. ofOne an of additional the first technologi source ofes energythat was on commercially board the vehicleintroduced in additionto increase to the coverage and reduce CO2 emissions at the same time was the hybrid drive (HEV) technique, in serial battery pack. or parallel configuration (Figure 1), combining the capabilities of the ICE and the electric motor. This Atconcept the endassumed of the the placement nineties, hybridof an additional vehicles source could of energy be found on board in the theofferings vehicle in addition of automotive to manufacturers.the battery pack. Currently, these designs are modified to increase the capacity of the battery pack with the possibilityAt the of end simultaneous of the nineties, charging hybrid from vehicles the power could grid be (PHEV).found in Withthe offerings the development of automotive of hybrid vehiclemanufacturers. technology Currently, (HEV, PHEV, these FCEV),designs are vehicles modified powered to increase exclusively the capacity from of the the battery battery pack pack with (BEV) werethe also possibility developed. of simultaneous The tendencies charging of the from governments the power grid that (PHEV). have recently With the been development observed of aim at eliminationhybrid vehicle of the ICE technology from the (HEV, propulsion PHEV, FCEV), systems. vehi Followingcles powered this exclusively line of reasoning, from the and battery knowing pack that according(BEV) towere statistics, also developed. more than The 80% tendencies of drivers of the do governments not travelmore that have than recently 65 km been per dayobserved [23], itaim would at elimination of the ICE from the propulsion systems. Following this line of reasoning, and knowing be possible to completely remove the ICE from the hybrid vehicle and install an additional battery that according to statistics, more than 80% of drivers do not travel more than 65 km per day [23], it pack or supercapacitor bank in its place, or a hydrogen tank feeding a fuel cell [24]. Bearing in mind would be possible to completely remove the ICE from the hybrid vehicle and install an additional constraintsbattery inpack the or form supercapacitor of proposals bank related in its place, to the or phasea hydrogen out oftank conventional feeding a fuel ICE cell propulsion[24]. Bearing units fromin vehicles, mind constraints and the lowin the range formof of BEVproposals vehicles, relate itd wasto the suggested phase out toof attachconventional a trailer ICE with propulsion a generator set orunits other from energy vehicles, source and [ 25the] tolow the range xEV of vehicle BEV vehicles, (Figure it3 was). Such suggested a solution to attach called a trailer range with extender a (RE, REX),generator or alternativelyset or other energy range source extending [25] to trailer-generator, the xEV vehicle (Figure long ranger,3). Such gena solution set trailer, called etc., range allows one toextender operate (RE, an REX), electric or alternatively vehicle over range long extendin distances,g trailer-generator, for example when long ranger, traveling gen betweenset trailer, cities. In built-upetc., allows areas, one however, to operate it an is electric always vehicle possible over to long detach distances, the range for example extender when range traveling (REX) between and use the batterycities. pack In installedbuilt–up areas, in the however, vehicle. it In is thealways world possible literature, to detach one the can range also extender find REs range in which (REX) reduction and use the battery pack installed in the vehicle. In the world literature, one can also find REs in which of greenhouse gas (GHG) emissions caused by the ICE used to increase the range of an electric vehicle reduction of greenhouse gas (GHG) emissions caused by the ICE used to increase the range of an is accomplished by powering them with liquefied petroleum gas (LPG), liquified natural gas (LNG), electric vehicle is accomplished by powering them with liquefied petroleum gas (LPG), liquified hydrogen,natural alcohol gas (LNG), or biofuels hydrogen, [26 alcohol]. or biofuels [26].
FigureFigure 3. Exemplary 3. Exemplary structure structure of of electrical electrical drivedrive system with with range range extender: extender: (a) (witha) with an internal an internal combustioncombustion generator; generator; (b )(b with) with a a package package ofof electricelectric batteries; batteries; (c ()c with) with a hydrogen a hydrogen cell; cell; (d) hybrid (d) hybrid systemsystem with with photovoltaic photovoltaic panels, panels, an an internal internal combustioncombustion generator, generator, a hydrogen a hydrogen cell celland anda packet a packet of of electricelectric batteries; batteries; (e) system(e) system pushing pushing a a tow tow vehicle, vehicle, with a a co combustionmbustion engine engine tran transmittingsmitting mechanical mechanical drivedrive to the to trailer’s the trailer’s wheels. wheels. BATT—Battery BATT–Battery Pack, Pack, EM—Electric EM–Electric Motor, Motor, HT–Hydrogen HT—Hydrogen Tank, Tank, FT–Fuel FT—Fuel Tank,Tank, FC—Fuel FC–Fuel Cell, PE—PowerCell, PE–Power Electronics, Electronic iWEM—Ins, iWEM–In Wheel ElectricWheel Motor, Electric T—Transmission, Motor, T–Transmission, ICE–Internal Combustion Engine; G–Generator; PE–Power Electronics. ICE—Internal Combustion Engine; G—Generator; PE—Power Electronics. The generator sets of these types can be placed directly on the xEV vehicle or onto an attached The generator sets of these types can be placed directly on the xEV vehicle or onto an attached trailer. One of the first actual designs using ICE–powered generators on a trailer was developed in trailer.1992 One by ofGage the from first AC actual Propulsion designs (San using Dimas, ICE-powered CA, USA) and generators Alan Cocconi on a (RXT) trailer [27], was the developed creator in 1992by Gage from AC Propulsion (San Dimas, CA, USA) and Alan Cocconi (RXT) [27], the creator of the technology currently used by Tesla, Inc.(Palo Alto, CA, USA) In 2011 at the Geneva Auto Show, Energies 2018, 11, x FOR PEER REVIEW 4 of 20 Energies 2018, 11, 2403 4 of 20
of the technology currently used by Tesla, Inc.(Palo Alto, CA, USA) In 2011 at the Geneva Auto Show, thethe SwissSwiss company company Rinspeed Rinspeed (Zurich, (Zurich, Swiss) Swiss) presented presented a conceptual a conceptual solution solution named named Dock +Dock Go which + Go werewhich colloquially were colloquially called “backpacks” called “backpacks” for small for city small cars city [28 ].cars [28]. AA similarsimilar solutionsolution was introduced by by EP EP Tender Tender (Poissy, (Poissy, France) France) in in 2013. 2013. The The developed developed REX REX is isequipped equipped with with a petrol a petrol engine engine driving driving a 25 a 25kW kW gene generatorrator to allow to allow an increase an increase of range of range of approx. of approx. 600 600km km(375 (375 miles) miles) for foran A an and A and B segment B segment electric electric car car[29]. [29 ]. InIn 20172017 BVB BVB INNOVATE INNOVATE GmBH GmBH (Blackesville, (Blackesville Swiss), Swiss) has has presented presented a solution a solution using using a trailer a trailer with awith package a package of batteries of batteries up to 85 up kWh to 85 that kWh can that power can up power the EV. up Batteries the EV. onBatteries the trailer on canthe betrailer charged can atbe fastcharged charging at fast stations charging [30 ]stations and can [30] also and be can used also as emergencybe used as emergency energy sources, energy (just sources, like the (just 13.5 like kWh the Powerwall13.5 kWh Powerwall by Tesla). Inby this Tesla). work, In thethis author work, presentsthe author the presents results ofthe research results relatedof research to the related application to the ofapplication a RE (placed of a upon RE (placed a trailer) upon for an a BEV.trailer) In orderfor an to BEV. reduce In order fuel consumption to reduce fuel and consumption cut down emissions and cut ofdown toxic emissions gases, the of technique toxic gases, of adding the technique steam and of adding oxyhydrogen steam gasand (HHO) oxyhydrogen to the intake gas (HHO) manifold to the of engineintake wasmanifold applied. of engine was applied.
2. 2. Methods Methods of of GHG GHG Reduction Reduction in in ICEs ICEs RegulationsRegulations aim aim to to reduce reduce greenhouse greenhouse gas (GHG)gas (GHG) emissions, emissions, which which mainly mainly include include carbon dioxidecarbon (COdioxide2), carbon (CO2), monoxidecarbon monoxide (CO), nitrogen (CO), nitrogen oxides (NO oxidesx), sulfur (NOx), oxides sulfur (SO oxidesx) volatile (SOx) non-methanevolatile non– organicmethane compounds organic compounds (NMVOC), (NMVOC), hydrocarbons hydrocarbons (HC), methane (HC), (CH methane4), and (CH particulate4), and particulate matter (PM) matter [31]. The(PM) simplest [31]. The solution simplest to reduce solution GHG to reduce emissions GHG isto emissions reduce the is consumptionto reduce theof consumption fuel used for of propulsion fuel used offor the propulsion vehicle. To of achieve the vehicle. this goal, To designers achieve this strive goal, to reduce: designers vehicle strive weight, to reduce: aerodynamic vehicle drag weight, and rollingaerodynamic resistance. drag Research and rolling is also resistance. being carried Research out is into also the being development carried out of into energy—efficient the development drive of motors,energy–efficient shift control drive algorithms, motors, shift or driving control stylealgorithms, of the vehicle or driving driver. style Another of the vehicle approach driver. involves Another the useapproach of various involves fuels orthe fuel use additives, of various as wellfuels asor substances fuel additives, and chemical as well compoundsas substances that and reduce chemical fuel consumptioncompounds that or reduce reduce toxic fuel emissions.consumption or reduce toxic emissions.
2.1.2.1. SteamSteam AdditionAddition toto thethe IntakeIntake ManifoldManifold ofof anan ICEICE OneOne ofof the the proposed proposed techniques techniques that that have have an an impact impact on on the the reduction reduction of pollutantsof pollutants emitted emitted by the by vehicle,the vehicle, is the ismethod the method employing employing the addition the addition of steam of steam to the to intake the intake manifold manifold [32], [32], water water injection injection into theinto intake the intake manifold manifold [33] or [33] application or application of 32.5% of urea32.5% solution, urea solution, known byknown the commercial by the commercial name AdBlue, name injectedAdBlue, automatically injected automatically into exhaust into manifoldexhaust manifold before the before Selective the Selective Catalytic Catalytic Reduction Reduction (SCR) catalyst (SCR) locatedcatalyst inlocated the exhaust in the gasexhaust line. gas With line. the With last of th thesee last AdBlue of these substances, AdBlue substances, there may there be problems may be relatedproblems to therelated decrease to the in effectivenessdecrease in effectiveness in the situation in the of system situation operation of system in extreme operation temperatures in extreme ortemperatures too long storage or too of long the fluid.storage When of the the fluid. airtemperature When the air drops, temperature the urea drops, crystals the start urea to crystals precipitate start ◦ ◦ into theprecipitate liquid. Anin the increase liquid. in An temperature increase in above temper 30atureC (86 aboveF) causes30 °C (86 a decrease °F) causes in a the decrease efficiency in the of theefficiency system, of as the a resultsystem, of as which a result harmful of which nitrogen harmful oxides nitrogen NOx and oxides particulate NOx and matter particulate (PM) escapematter into(PM) the escape atmosphere into the [ 34atmosphere]. These emissions [34]. These can emissions be reduced can by be installation reduced by of installation PM filters of in PM the exhaustfilters in line.the exhaust The presented line. The technique presented of technique reduction of of reductio pollutantsn of bypollutants an ICE assumesby an ICE the assumes supply the of supply steam orof watersteam injectionor water into injection its intake into airits manifoldintake air or manifold combustion or combustion chamber. In chamber. the case ofIn steamthe case technology, of steam thetechnology, energy required the energy to produce required it, to is produce taken from it, is the taken exhaust from of the the exhaust engine andof the supplied engine toand the supplied tank in whichto the watertank in is which stored water (Figure is 4stored). The (Figure amount 4). of The steam amount supplied of steam to the supplied intake manifold to the intake of the manifold engine airof the can engine be dosed air viacan a be solenoid dosed via valve a solenoid controlled valve by acontrolled PLC or a microcontroller.by a PLC or a microcontroller.
FigureFigure 4.4. Block diagram of the systemsystem forfor steamsteam deliverydelivery toto thethe intakeintake manifoldmanifold ofof anan internalinternal combustioncombustion engineengine (ICE).(ICE).
EnergiesEnergies2018 2018, 11, 11, 2403, x FOR PEER REVIEW 5 of5 of 20 20 Energies 2018, 11, x FOR PEER REVIEW 5 of 20 As part of the conducted tests, two engines of generator sets were tested: one running on petrol As part of the conducted tests, two engines of generator sets were tested: one running on petrol and Asanother part of one the on conducted diesel fuel. tests, The two composition engines of of generator exhaust setsgases were was tested: tested oneusing running the MRU on petrol 95/2D and another one on diesel fuel. The composition of exhaust gases was tested using the MRU 95/2D andanalyzer. another Figure one on 5 shows diesel fuel.the content The composition of pollutants of exhaustemitted gasesby the was engine tested of usinga generator the MRU in both 95/2D the analyzer. Figure 5 shows the content of pollutants emitted by the engine of a generator in both the analyzer.petrol and Figure diesel5 versions.shows the content of pollutants emitted by the engine of a generator in both the petrolpetrol and and diesel diesel versions. versions.
FigureFigure 5. 5. Content of pollutants in exhaust gases of a diesel generator set. Figure 5.Content Content ofof pollutantspollutants inin exhaustexhaust gases gases of of a a diesel diesel generator generator set. set. 2.2.2.2. Oxy-Hydrogen Oxy–Hydrogen (HHO) (HHO) in in Intake Intake Manifold Manifold of of ICE ICE 2.2. Oxy–Hydrogen (HHO) in Intake Manifold of ICE AnotherAnother wayway toto reducereduce thethe emission emission ofof toxictoxic substancessubstances fromfrom anan ICEICE is is the the method method using using the the Another way to reduce the emission of toxic substances from an ICE is the method using the additionaddition of of HHO HHO gas gas into into the the air air intake intake manifold manifold of of the the ICE ICE [ 35[35,36].,36]. The The electrical electrical energy energy necessary necessary addition of HHO gas into the air intake manifold of the ICE [35,36]. The electrical energy necessary toto produce produce the the HHO HHO gas gas in in the the electrolysis electrolysis process process is is supplied supplied fromfrom anan alternatoralternator drivendriven byby anan ICE,ICE, to produce the HHO gas in the electrolysis process is supplied from an alternator driven by an ICE, toto which which the the gas gas is is then then fed fed (Figure (Figure6 ).6). to which the gas is then fed (Figure 6).
FigureFigure 6. 6.Block Block diagram diagram of of the the system system for for oxyhydrogen oxyhydrogen (HHO) (HHO) gas gas delivery delivery to to the the intake intake manifold manifold of of Figure 6. Block diagram of the system for oxyhydrogen (HHO) gas delivery to the intake manifold of anan ICE ICE together together with with diagram diagram of of the the HHO HHO gas gas generation generation system. system. an ICE together with diagram of the HHO gas generation system. SometimesSometimes there there are are solutions solutions in in which which the the hydrogen hydrogen is is supplied supplied directly directly to to the the engine engine from from the the Sometimes there are solutions in which the hydrogen is supplied directly to the engine from the gasgas cylinder cylinder [ 37[37,38].,38]. AsAs partpart ofof thethe tests, tests, thethe same same two two generators generators withwith petrolpetrol and and diesel diesel fuel fuel types types gas cylinder [37,38]. As part of the tests, the same two generators with petrol and diesel fuel types werewere tested. tested. As As in in the the case case of of steam steam addition addition measurements, measurements, the the composition composition of of exhaust exhaust gas gas content content were tested. As in the case of steam addition measurements, the composition of exhaust gas content waswas tested tested using using the the MRU MRU 95/2D 95/2D analyzer.analyzer. FiguresFigures7 7and and8 show8 show the the content content of of pollutants pollutants emitted emitted by by was tested using the MRU 95/2D analyzer. Figures 7 and 8 show the content of pollutants emitted by enginesengines of of petrol petrol generator generator and and diesel diesel generator. generator. Hybrid Hybrid technologies technologies are are a a form form of of substitute substitute for for the the engines of petrol generator and diesel generator. Hybrid technologies are a form of substitute for the fewfew disadvantages disadvantages of of BEV, BEV, which which include include relatively relatively low low range. range. few disadvantages of BEV, which include relatively low range.
Energies 2018, 11, x FOR PEER REVIEW 6 of 20 EnergiesEnergies2018 2018, ,11 11,, 2403 x FOR PEER REVIEW 66 of of 20 20 Energies 2018, 11, x FOR PEER REVIEW 6 of 20
Figure 7. The amount of pollutants in the exhaust gases of a generator set with a gasoline engine. Figure 7. The amount of pollutants in the exhaust gases of a generator set with a gasoline engine. Figure 7. The amount of pollutants in the exhaust gases of a generator set with a gasoline engine. Figure 7. The amount of pollutants in the exhaust gases of a generator set with a gasoline engine.
Figure 8. The amount of pollutants in the exhaust gases of a diesel generator set. FigureFigure 8.8. TheThe amountamount ofof pollutantspollutants inin thethe exhaustexhaust gasesgases ofof aa dieseldiesel generatorgenerator set.set. Figure 8. The amount of pollutants in the exhaust gases of a diesel generator set. 3. Modeling 3. Modeling 3. ModelingIn orderorder toto model model a vehiclea vehicle with with a trailer a trailer in motion, in motion, the forces the forces acting acting on both on constructions both constructions during In order to model a vehicle with a trailer in motion, the forces acting on both constructions theirduring movement their movement should beshould taken be into taken account into account (Figure 9(Figure). 9). duringIn theirorder movement to model shoulda vehicle be takenwith ainto trailer account in motion, (Figure the 9). forces acting on both constructions during their movement should be taken into account (Figure 9).
Figure 9. Forces acting on a moving vehicle with trailer. Figure 9. Forces acting on a moving vehicle with trailer. Figure 9. Forces acting on a moving vehicle with trailer. The basic forces include those that are related to aerodynamic resistance, rolling resistance, sliding The basic forces includeFigure those 9. Forces that acting are related on a moving to aerodynamic vehicle with trailer.resistance, rolling resistance, resistance, inertia resistance and resistances of the mechanisms in the propulsion system. For the slidingThe resistance, basic forces inertia include resistance those and that resistances are related of theto aerodynamic mechanisms inresistance, the propulsion rolling system. resistance, For vehicleThe to bebasic able forces to move, include the sum those of forcesthat are associated related withto aerodynamic the resistances resistance, must be lessrolling than resistance, the force thesliding vehicle resistance, to be able inertia to move, resistance the sum and of resistances forces associated of the mechanisms with the resistances in the propulsion must be less system. than theFor generatedsliding resistance, by the propulsion inertia resistance system. Tableand resistances1 gives a description of the mechanisms of the symbols in the used propulsion and their system. meaning. For forcethe vehicle generated to be by able the to propulsion move, the sumsystem. of forces Table associated1 gives a description with the resistances of the symbols must beused less and than their the the vehicle to be able to move, the sum of forces associated with the resistances must be less than the meaning.force generated by the propulsion system. Table 1 gives a description of the symbols used and their force generated by the propulsion system. Table 1 gives a description of the symbols used and their meaning. meaning.
Energies 2018, 11, 2403 7 of 20
Table 1. Symbols and their meaning.
Symbol Description Unit Symbol Description Unit Traction force acting on a Acceleration of the vehicle m/s2 F N TV the vehicle 2 2 AV Frontal area of the vehicle m g Standard gravity m/s 2 AT Frontal area of the trailer m HsD Calorific value of diesel fuel J/kg
CdV Vehicle drag coefficient – HsP Calorific value of petrol fuel J/kg
CdT Trailer drag coefficient – IB Battery current A Electrical energy produced by E J I Motor phase RMS current A REXD diesel generator M Electrical energy produced by Torque at clutch at rated EREXP J MC Nm petrol generator speed ωnC Torque at drive shafts at rated FAD Total aerodynamic drag force N MDS Nm speed ωnDS Torque at gearbox output FADT Trailer aerodynamic drag force N MF Nm shaft at rated speed ωnF Torque produced by the F Vehicle aerodynamic drag force N M Nm ADV M electric motor The force acting on the moving FDL vehicle as a result of friction in the N mFD Mass of consumed diesel fuel kg transmission system
FGRT Weight of the trailer N mFP Mass of consumed petrol fuel kg Trailer with range F Weight of the vehicle N m kg GRV T extender weight Force inertia of the vehicle and F N m Vehicle weight kg IN trailer system V Motive force created by the Final drive F N n – M driven wheels F (differential gear) ratio
FNT Normal force of the trailer N nG Current transmission ratio –
FNV Normal force of the vehicle N PB Battery power W Chemical power flow of F Total resistance of the vehicle N P W R FD diesel fuel Chemical power flow of petrol F Total rolling resistance N P W RR FP fuel Diesel engine driven F Rolling resistance of trailer wheels N P W RRT REXD generator power Rolling resistance of vehicle Petrol engine driven generator F N P W RRV wheels REXP power
FS Total sliding force N PI Inverter power W
FST Sliding force acting on the trailer N PM Motor power W
FSV Sliding force acting on the vehicle N RV Vehicle wheel radius M
FTT Traction force acting on the trailer N RT Trailer radius of the trailer M Trailer wheels rolling U Battery voltage V µ – B RRT resistance coefficient v Vehicle speed m/s ρ Ambient air density kg/m3 Clutch and input gearbox α Road inclination deg. ω rad/s C shaft rotation speed Average speed of wheel η Battery efficiency – ω rad/s B DS drive shafts Diesel genset (engine + generator Gearbox output shaft η – ω rad/s GD set) efficiency F rotation speed Petrol genset (engine + generator Nominal rotational speed of η – ω rad/s GP set) efficiency nC the clutch Nominal rotational speed of η Inverter efficiency – ω rad/s I nDS wheel drive shafts Nominal rotational speed of η Motor efficiency – ω rad/s M nF the gearbox output Vehicle wheels rolling µ – RRV resistance coefficient Energies 2018, 11, 2403 8 of 20
The forces acting on the vehicle combination can be expressed on the basis of the relationship:
FR = FAD + FRR + FS + FDL + FIN (1)
The aerodynamic drag forces for the vehicle combination were determined from the equations:
FAD = FADV + FADT (2)
ρ·v2 F = (C ·A + C ·A )· (3) AD dV dT T 2 The rolling resistance forces for the vehicle combination were determined based on the dependence:
FRR = FRRV + FRRT (4)
µRRV µRRT FRR = mV ·g· · cos(α) + mT·g· · cos(α) (5) R RT The sliding forces for the vehicle combination are based on:
FS = FSV + FST (6)
FS = (mV + mT)·g· sin(α) (7) The resistance forces of the transmission system related to the movement of the vehicle combination were determined basing on:
ωC ωF ωDS FDL = R·(MC· + MF· + MDS· ) (8) ωnC ωnF ωnDS wherein: ωC = ωF·nG (9)
ωF = ωDS·nF (10) nG·nF nF 1 FDL = R·ωDS· MC· + MF· + MDS· (11) ωnC ωnF ωnDS Inertia resistance forces related to the acceleration and braking of the vehicle combination were obtained based on: FIN = mV ·a + mT·a = (mV + mT)·a (12) The source of the driving force is the torque generated by the electric motor driving the wheels through: clutch, gearbox, differential and drive axles:
MM·nG·nF FM = (13) RV
The driving power on the wheels is equal to the product of the linear speed v and the driving force FM: PV = v·FM (14)
Since the losses of the transmission are taken into account in the description of the FDL force, it can be assumed that the propulsive power on the wheels is equal to the driving power generated by the vehicle’s engine: PM = PV (15) Energies 2018, 11, 2403 9 of 20
The power of the electric drive motor is equal to the power generated by the inverter minus the efficiency of the motor at a given operating point. The motor power is equal to the product of the engine torque and its rotational speed:
PM(t) = PI (t)·ηM(IM, ωC) = MM(t)·ωC(t) (16)
The power generated by the inverter is equal to the power taken from the battery pack and generators decreased by the efficiency factor of the inverter:
PI (t) = (PB(t) + PG(t))·ηI (17)
The power drawn from the battery pack is equal to the product of the current flowing through the battery and its voltage reduced by the efficiency coefficient:
PB(t) = UB(t)·IB(t)·ηB (18)
The power generated by the generator sets is equal to the product corresponding to the power of the fuel consumed and the efficiency of the generating set:
PGP(t) = PFP(t)·ηGP (19)
PGD(t) = PFD(t)·ηGD (20) By generating electricity, the RE consumes fuel-petrol or diesel. Depending on the type of fuel selected, the parameters of the efficiency of fuel-energy conversion and the calorific value of a kilogram of fuel are defined. The chemical power flow for petrol and diesel fuel, PFP and PFD, respectively, is defined as the product of the weight of fuel burned over time of mFD’(t) and mFP’(t) respectively and the corresponding calorific value of fuel HsD and HsP. The mass of fuel consumed and energy produced from it by RE is determined by the equation:
t R EREXD(t) = PREXD(t)·dt 0 t E (t) = R P (t)·dt REXP REXP 0 t ( ) m = R EREXD t ·dt FD ηGD·HsD (21) 0 t R EREXP(t) mFP = ·dt ηGP·HsP 0 . PFD(t) = mFD(t)·HsD . PFP(t) = mFP(t)·HsP
The calorific value H for diesel fuel equals: HsD = 38 MJ/kg, and for unleaded petrol equals: HsP = 32 MJ/kg. Based on the mass of fuel consumed and the CO2 emission factor for diesel fuel (EFD) and petrol (EFP), the mass of emitted carbon dioxide generated by the generating set (diesel—mCO2D), petrol—mCO2P) is calculated as well as the total mass of the emitted carbon dioxide (mCO2). m = m ·EF CO2D FD D mCO2P = mFP·EFP (22) mCO2 = mCO2D + mCO2P Energies 2018, 11, x FOR PEER REVIEW 10 of 20
petrol–mCO2P) is calculated as well as the total mass of the emitted carbon dioxide (mCO2).