ELEC­TRIC PO­TEN­TIAL

At the im­pend­ing 67th IAA Com­mer­cial Ve­hi­cles Show this Septem­ber in Han­nover, Ger­many, elec­tric ve­hi­cles will be big news – and not just pro­to­types. Two in par­tic­u­lar will stand out for dif­fer­ent rea­sons One will be the evo­lu­tion of the best-sell­ing low-

ABC (Australia) - - CONTENTS - WORDS FABIAN COT­TER / IM­AGES DAIM­LER + MAN

At the forth­com­ing IAA Com­mer­cial Ve­hi­cles show in Ger­many, two elec­tric buses will be rais­ing the flag for the lo­cals. The Mercedes-Benz eCi­taro and the MAN Lion’s City E. Will they be the gamechang­ers they prom­ise to be? Fabian Cot­ter re­ports.

ALOT HAS HAP­PENED in five years, in terms of elec­tric ve­hi­cle de­vel­op­ment. Why five years? Why not 10? Or 35, or even more? In­deed, why not? Sci­en­tists have dab­bled with ex­per­i­ments and ad­vances in battery pro­duc­tion and elec­tric­ity max­imi­sa­tion since Ben­jamin Franklin first zapped him­self via his kite dur­ing his fa­mous thun­der­storm ex­per­i­ment in 1752.

Yet ar­guably the mag­ni­tude of such ad­vances only dawned on main­stream

so­ci­ety through­out the years once it prof­fered a prac­ti­cal and tan­gi­ble en­hance­ment to the way we lived.

Light­bulbs be­ing a doozy of an ex­am­ple, and many are just ap­pre­ci­at­ing now the of­ten largely un­ap­pre­ci­ated work of Nikola Tesla about 150 years after Ben­ji­boy Franklin.

Global en­vi­ron­men­tal con­cern for the planet and car­bon emis­sions in the mod­ern era has seen the ma­jor­ity of those who tra­di­tion­ally needn’t care about how, why and where their elec­tric­ity comes from ev­ery time they flick the switch in their bath­rooms for the Ur­ban Dic­tionary’s ‘three S’s’ each morn­ing, to seem­ingly cov­et­ing any morsel of news about elec­tric­ity ad­vances be­ing the panacea to a fos­sil-fuel-free fu­ture.

More than 190 nations signed the legally bind­ing 1997 Ky­oto Pro­to­col to fight cli­mate change and now, three years after it was agreed, since July 2018 195 United Nations Frame­work Con­ven­tion of Cli­mate Change (UNFCC) mem­bers have signed the Paris Agree­ment – and 179 have be­come a party to it. Add on two years prior to 2015 for some poor per­son to type up said agree­ment to get it ready – prob­a­bly on a dot ma­trix type­writer to save elec­tric­ity any­way – and there’s your five years right there.

With the agree­ment’s cen­tral aim to, “strengthen the global re­sponse to the threat of cli­mate change by keep­ing a global tem­per­a­ture rise this cen­tury well be­low 2 de­grees Cel­sius above prein­dus­trial lev­els and to pur­sue ef­forts to limit the tem­per­a­ture in­crease even fur­ther to 1.5 de­grees Cel­sius,” the clock is tick­ing. The year 2030 is a uni­ver­sal dead­line for many coun­tries and

gov­ern­ments to gauge mean­ing­ful car­bon-re­duc­tion achieve­ment – or maybe not.

And with the lat­est Bloomberg New En­ergy Fi­nance re­port ex­pect­ing sales of elec­tric cars to surge to 28 per cent world­wide, but most in­ter­est­ingly elec­tric buses to rocket to a mas­sive 84 per cent of their re­spec­tive global mar­kets by 2030, ve­hi­cles just like the new Mercedes-Benz eCi­taro and MAN Lion’s City elec­tric could prove key.

FROM LOW TO NO EMIS­SIONS

From what we’ve seen and heard thus far since a re­cent Daim­ler pre­view event, the new eCi­taro has plenty go­ing for it. Ba­si­cally, it gets a tai­lor-made ex­clu­sive ex­te­rior; flex­i­ble charg­ing tech­nol­ogy – plugin charg­ing as stan­dard, op­tional pan­to­graph; new ap­proaches for heat­ing and cli­mate con­trol; and a prac­ti­cal range also un­der dif­fi­cult con­di­tions, ac­cord­ing to Daim­ler.

“It emits zero lo­cal emis­sions and runs al­most silently. It com­bines the thou­sand­fold proven plat­form of the world’s best-sell­ing city bus with new tech­no­log­i­cal so­lu­tions,” the com­pany states.

“The all-elec­tric Mercedes-Benz eCi­taro takes elec­tric mo­bil­ity us­ing city buses to a new level al­to­gether,” and it, “of­fers an im­pres­sive and un­prece­dented stan­dard in en­ergy ef­fi­ciency, cour­tesy of its in­no­va­tive ther­mal man­age­ment sys­tem that uses in­no­va­tive com­po­nents avail­able for the first time with the launch of the eCi­taro.”

How this all trans­lates in the real world Euro­pean op­er­a­tors (mostly) will know soon enough, but on pa­per it sounds like an in­trigu­ing piece of kit.

“Its per­for­mance en­ables the eCi­taro to cover a large part of the re­quire­ments of the trans­port op­er­a­tors right from the start. In ad­di­tion, it is ready for the

…buses like the new Mercedes-Benz eCi­taro and MAN Lion’s City elec­tric are key.

battery tech­nol­ogy of the near fu­ture – the per­for­mance ca­pa­bil­i­ties will in­crease quickly.”

“Its de­sign fuses the ba­sic shape of the Ci­taro with el­e­ments of the Mercedes-Benz Fu­ture Bus into a dis­tinct ap­pear­ance. It is also more than just a city bus: Mercedes-Benz takes a holis­tic view of elec­tric mo­bil­ity, em­bed­ding the eCi­taro firmly in its over­all eMo­bil­ity sys­tem. In ad­di­tion, the eCi­taro is the start­ing sig­nal on the road to an elec­tric fu­ture,” the com­pany states.

Daim­ler says the eCi­taro will be an im­por­tant el­e­ment in any ‘wellde­vel­oped’ lo­cal pub­lic trans­port in­fra­struc­ture, with low-emis­sion and lo­cally emis­sion-free buses.

Based on the con­cept of a reg­u­lar Ci­taro – the world’s best-sell­ing city bus with more than 50,000 units sold – the eCi­taro joins the large-ca­pac­ity Ca­paC­ity bus, as well as the Ci­taro hy­brid and the Ci­taro NGT in show­cas­ing Daim­ler’s “highly so­phis­ti­cated level of de­vel­op­ment of pow­er­trains”, said to be “char­ac­terised by both their ef­fi­ciency of op­er­a­tion and their low emis­sions”.

“The all-elec­tric eCi­taro is now taking the next step from low-emis­sion bus to lo­cally emis­sion-free bus.”

EX­CLU­SIVE EX­TE­RIOR?

Fun­da­men­tally, the eCi­taro mar­ries ex­te­rior de­sign el­e­ments of a nor­mal mod­ern Ci­taro with that of the stylis­ti­cally bound­ary-push­ing Fu­ture Bus Con­cept, its au­ton­o­mous bus project. At the front, a 28cm Mercedes star high­lights at­trac­tive light­ing ef­fects from dif­fer­ent an­gles and in chang­ing sun­light, with the star, the trim el­e­ments and the Mercedes-Benz badge em­bed­ded into the high-gloss black front panel, in­te­grated with in­di­vid­ual LED head­lamps. The model lo­go­type with a blue ‘e’ in­di­cates the al­l­elec­tric pow­er­train.

Its curved wind­screen smoothly tran­si­tions into the roof with dark bars on the left and right. At its mid­dle, the roof sports an ‘is­land’ in ve­hi­cle colour that forms the roof mem­brane. A multi-piece roof-edge ridge hides the roof-mounted equip­ment. Fur­ther ‘op­ti­cal tricks’ lend the eCi­taro “per­fect pro­por­tions and make it seem light,” the com­pany states.

IN­SIDE STORY

In the pas­sen­ger com­part­ment, the eCi­taro fea­tures a gen­eral up­date of the in­te­rior of the en­tire Ci­taro fam­ily. The ‘cof­fered’ de­sign ceil­ing above the cen­tre aisle and the sweep­ing roof-edge flaps hide a new air-cir­cu­la­tion sys­tem with tex­tile ducts in place of the cur­rent plas­tic air ducts. They are said to be even eas­ier and sim­pler to in­stall.

In ad­di­tion to the closed look and the new in­te­rior lights, the ad­van­tage of the new ceil­ing is a sig­nif­i­cantly re­duced num­ber of in­di­vid­ual parts.

To­gether with the new air-cir­cu­la­tion sys­tem, this low­ers the al­ready low in­te­rior noise in the pas­sen­ger com­part­ment even fur­ther, which means more com­fort, it’s claimed.

Also new is the black trim on the sills and win­dow posts. As a re­sult, the

win­dow posts are said to stand out less and the ap­pear­ance of the side walls is “calmed”.

While the new ex­te­rior was de­signed and de­vel­oped ex­clu­sively for the eCi­taro, Mercedes-Benz will trans­fer the changes in the in­te­rior to the en­tire model se­ries.

MO­TIVE MACHINATIONS

The new eCi­taro uses a ZF AVE 130 elec­tric por­tal axle with mo­tors at the wheel hubs. The peak out­put of the mo­tors is 2x125kW, while torque is 2x485Nm.

Lithium-ion bat­ter­ies with a to­tal ca­pac­ity of up to about 243kWh pro­vide the power. They are mod­u­lar in de­sign; the bat­ter­ies are split be­tween up to 10 mod­ules, each sup­ply­ing around 25kWh. As well as two battery mod­ules on the ve­hi­cle roof, the stan­dard equip­ment in­cludes four mod­ules in the rear of the bus. In the eCi­taro th­ese take the place of a com­bus­tion en­gine and trans­mis­sion. De­pend­ing upon cus­tomer re­quire­ments, an­other two or four battery mod­ules are mounted on the roof of the eCi­taro, says Daim­ler.

Each battery mod­ule is made up of 15-cell mod­ules, as well as “a con­trol unit for mon­i­tor­ing pur­poses and as a means of bal­anc­ing the charge of the battery cells”. Each sep­a­rate cell mod­ule houses 12 battery cells. MercedesBenz uses pris­matic cells with a ca­pac­ity of 37Ah each.

With a min­i­mum of six and up to a max­i­mum of 10 pos­si­ble battery mod­ules, trans­port op­er­a­tors can adapt their us­age and charg­ing strat­egy very pre­cisely to in­di­vid­ual needs, it’s claimed. Opt­ing for the largest num­ber max­imises the range of the buses, while a smaller num­ber re­duces the weight as well as the cost of pur­chase and al­lows more space for pas­sen­gers – but po­ten­tially makes time-con­sum­ing op­por­tu­nity charg­ing nec­es­sary, the com­pany ex­plains.

With the max­i­mum com­ple­ment of 10 battery mod­ules, the eCi­taro in stan­dard spec­i­fi­ca­tion weighs around 13.44 tonnes. In con­junc­tion with a gross ve­hi­cle weight rat­ing of 19.5 tonnes, this cor­re­sponds to a pay­load of more than six tonnes or around 88 pas­sen­gers – in line with what is needed in prac­tice even dur­ing rush hour, it states.

FLEX­I­BLE CHARG­ING

For the start of eCi­taro se­ries pro­duc­tion, plug-in charg­ing is

in­tended. To this end, the city bus fea­tures a socket for a Combo-2 plug above the front wheel arch on the right-hand side of the ve­hi­cle in the di­rec­tion of travel as per the pro­vi­sions of the Ger­man As­so­ci­a­tion of Pub­lic Trans­port Op­er­a­tors (VDV). This en­sures the sim­plest, fastest and at the same time cheaper power sup­ply vari­ant, the com­pany says.

If op­por­tu­nity charg­ing is re­quired to ex­tend the range, there will also be an op­tion to charge the eCi­taro via a pan­to­graph in fu­ture. This op­tion will be grad­u­ally phased in once se­ries pro­duc­tion has started.

There will be two pos­si­ble vari­ants: in phase 1, an in­te­gral pan­to­graph on the roof; in phase 2, charg­ing rails on the roof that will al­low charg­ing via a sta­tion­ary pan­to­graph of a charg­ing sta­tion. In both cases, the in­stal­la­tion space will be level with the front axle.

This in­tel­li­gent mod­u­lar con­cept of battery and charg­ing tech­nol­ogy means Mercedes-Benz is able to of­fer trans­port op­er­a­tors the op­por­tu­nity to con­fig­ure the eCi­taro pre­cisely to the in­di­vid­ual re­quire­ments of the com­pany or even of in­di­vid­ual routes, it’s stated.

In ad­di­tion, the eCi­taro is also able to gen­er­ate elec­tri­cal en­ergy through an en­ergy re­cov­ery process. In this case, those two elec­tric mo­tors at the wheel hubs of the drive axle act as al­ter­na­tors dur­ing brak­ing, trans­form­ing the ki­netic en­ergy of the ve­hi­cle into elec­tric­ity.

MAN’s de­but­ing Lion’s City elec­tric will pack a whop­ping 480kWh, 640kWh for the ar­tic.

BATTERY HEAT

Bat­ter­ies at their ideal tem­per­a­ture give max­i­mum per­for­mance and ser­vice life, so ther­mal man­age­ment is im­por­tant.

Mercedes-Benz cools the bat­ter­ies to en­sure that they re­main at the ideal tem­per­a­ture, thereby en­sur­ing max­i­mum charg­ing ca­pac­ity, per­for­mance ca­pa­bil­ity, and ser­vice life, it’s stated.

“This cool­ing is un­der­taken by a sep­a­rate battery cooler mounted on the roof. At ex­treme out­side tem­per­a­tures, the stan­dard pas­sen­ger-com­part­ment cli­mate con­trol sys­tem is used to boost the cool­ing of the bat­ter­ies.”

PRAC­TI­CAL RANGE

Oper­at­ing range fig­ures for all-elec­tricpow­ered city buses are of­ten dif­fi­cult to com­pare and cau­tion is ad­vised, since ref­er­ence val­ues can be miss­ing and the fig­ures have of­ten been cal­cu­lated un­der ideal con­di­tions, says Daim­ler Bus.

For the eCi­taro, in the in­ter­ests of re­li­able data, Mercedes-Benz prefers to con­sider a “worst-case sce­nario” and there­fore takes its di­rec­tion from the chal­leng­ing stan­dard­ised city driv­ing cy­cle known as SORT2. To make things even trick­ier, Mercedes-Benz also adds the en­ergy re­quire­ments of the an­cil­lary con­sumers into the equa­tion.

Ac­cord­ing to SORT2, the Ci­taro with a full com­ple­ment of bat­ter­ies achieves an oper­at­ing range of around 150 kilo­me­tres in the [Euro­pean] sum­mer.

In other words, it is al­ready pos­si­ble to serve some sub-net­works within the daily work­load of a city bus with­out op­por­tu­nity charg­ing.

With­out op­por­tu­nity charg­ing, the eCi­taro al­ready cov­ers about one third of all re­quire­ments of the trans­port op­er­a­tors. That is, it can seam­lessly re­place one in three city buses

pow­ered by a com­bus­tion en­gine. Un­der ideal con­di­tions, the eCi­taro even drives around 250 kilo­me­tres with­out op­por­tu­nity charg­ing, it’s claimed.

eCi­taro testing saw engi­neers also eval­u­ate the com­pat­i­bil­ity of the bus with dif­fer­ent charg­ing sys­tems. It

en­sures the eCi­taro com­mu­ni­cates in ac­cor­dance with ISO 15118 stan­dard, with the charg­ing sta­tion com­mu­ni­cat­ing with the con­trol unit of the eCi­taro.

BAT­TER UP!

Rapid battery tech­nol­ogy pro­gres­sion means the eCi­taro is ready for such ad­vance­ment. Lithium-ion bat­ter­ies with lithium nickel man­ganese cobalt ox­ide cells (NMC) are cur­rently in use, it’s stated.

On the eCi­taro, they have a bal­anced mix of en­ergy den­sity and si­mul­ta­ne­ous quick-charg­ing ca­pa­bil­ity. The ‘next gen’ of NMC bat­ter­ies with larger ca­pac­ity and in­creased range will be pro­vided to cus­tomers of the eCi­taro after reach­ing pro­duc­tion readi­ness.

With 33kWh per battery mod­ule and a re­sult­ing to­tal ca­pac­ity of up to 330kWh, the eCi­taro will then cover about 50 per cent of all ap­pli­ca­tions, it’s stated.

This greater battery ca­pac­ity also makes a mean­ing­ful in­tro­duc­tion of an eCi­taro G ar­tic­u­lated bus with a rea­son­able range pos­si­ble. Fu­ture lithium-poly­mer bat­ter­ies are op­tions. Th­ese ‘solid state’ bat­ter­ies fea­ture an es­pe­cially long ser­vice life and high en­ergy den­sity.

With a rated battery ca­pac­ity of about 400kWh and more in the ar­tic­u­lated bus, eCi­taro will then meet about 70 per cent of all re­quire­ments with­out op­por­tu­nity charg­ing, it’s stated.

Solid-state bat­ter­ies are not in­ter­change­able with NMC and not suit­able for quick charg­ing. As a re­sult, eCi­taro in fu­ture will be of­fered with a choice of ei­ther.

Sub­se­quently, the eCi­taro range will be in­creased yet again through a fuel cell that gen­er­ates elec­tric­ity. De­signed to al­low nearly 100 per cent of all re­quire­ments on city buses, this elim­i­nates the need for op­por­tu­nity charg­ing and com­plex in­fra­struc­ture re­quired else­where.

Start of se­ries eCi­taro pro­duc­tion is still planned by the end of 2018, with ini­tial or­ders re­ceived, it’s stated. First cus­tomer de­liv­er­ies will also start be­fore the year is out.

Above: Not a bad­look­ing in­te­rior, that one; Driver dis­play gives all that’s needed.

Top: Fu­ture­proofed for op­por­tu­nity charg­ing via pan­to­graph.

Above: Se­ries pro­duc­tion will use plug-in charg­ing. Note Combo-2 socket above the front wheel arch on the right-hand.

Above:No en­gine in here, it’s all about elec­tric mo­tors on such buses now.

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