In­dus­try gears up for a lighter foot­print

Cost, con­ve­nience and tech­nol­ogy are re­strict­ing the com­mer­cial ap­peal of en­vi­ron­men­tally friendly mod­els, writes Philip Lord

The Weekend Australian - Review - - Clean Energy -

THE car is about to un­dergo revo­lu­tion­ary change, the most sig­nif­i­cant since the world’s first car, built by Karl Benz, coughed into life in 1886. In 2007, the car’s con­tri­bu­tion to detri­men­tal global CO lev­els is well- doc­u­mented. For­tu­nately, there are many new in­no­va­tive paths car com­pa­nies are walk­ing down to re­duce the car’s car­bon foot­print.

While it ap­pears plau­si­ble that we will all drive zero- emis­sions elec­tric cars in some form or an­other in 15 years, at the mo­ment prob­lems with cost, con­ve­nience and bat­tery tech­nol­ogy are re­strict­ing their mass- mar­ket ap­peal. Bridg­ing the gap be­tween ex­ist­ing cars and the elec­tric cars are cleaner, more ef­fi­cient de­vel­op­ments based on present tech­nol­ogy.

For ex­am­ple, Volk­swa­gen has re­cently taken two well- known per­for­mance tech­nolo­gies and suc­cess­fully mar­ried them not only for driv­ing plea­sure but also for the en­vi­ron­ment. The Volk­swa­gen Golf’s Twin­charger TSI en­gine is both tur­bocharged and su­per­charged — which has been done be­fore in high- per­for­mance ap­pli­ca­tions, but never in a run- of- the- mill road car en­gine that dis­places only 1.4 litres.

The tur­bocharger and su­per­charger are both air pumps — pump­ing in air into the cylin­ders, squeez­ing in ev­ery last bit of air and, in con­junc­tion with a so­phis­ti­cated, high- pres­sure di­rect fuel in­jec­tion sys­tem, makes the en­gine highly ef­fi­cient. A tur­bocharger, driven by the en­gine’s ex­haust gases, does not work well at low revs when ex­haust gas out­put is low, while the op­po­site is true of a su­per­charger, which is driven from the en­gine via a belt drive. The clever part of the TSI en­gine is that its su­per­charger and tur­bocharger work in se­ries, mak­ing the most of their re­spec­tive strengths and ef­fi­ciency. De­pend­ing on en­gine load, the su­per­charger is dis­en­gaged by a mag­netic clutch by 2400 rpm, by which time the tur­bocharger has built- up pres­sure and can do its best air- pump­ing work up to the en­gine’s 7000rpm red­line.

The beauty of this tech­nol­ogy is that it al­lows you to put your foot down with­out leav­ing a huge car­bon foot­print. For a small 1400cc petrol four- cylin­der en­gine, the TSI’s out­puts are star­tling: 125kW and 240Nm of torque be­tween 1750 and 4500rpm. Claimed fuel con­sump­tion is 7.7L/ 100km, 0- 100km is achieved in 7.9 sec and CO out­put is 183g per km. Volk­swa­gen claims that per­for­mance com­pares with a 2.3- litre en­gine, but fuel con­sump­tion and emis­sions are 20 per­cent less. Volk­swa­gen’s own nat­u­rally as­pi­rated Golf 2.0- litre is slower, thirstier and emits more CO2.

The mod­ern turbo- diesel en­gine is known for its ex­cel­lent torque and fuel- burn­ing ef­fi­ciency with cor­re­spond­ing low fuel con­sump­tion and CO2 emis­sions, but it’s also well­known for emit­ting rel­a­tively high lev­els of pol­lu­tants such as nitro­gen ox­ides and diesel par­tic­u­lates, or soot.

Mercedes- Benz may have the so­lu­tion to this diesel dilemma in the form of its BlueTec tech­nol­ogy, in­tro­duced last year and most re­cently shown at the 2007 Geneva Show as the Vi­sion C220 BlueTec.

The C220 BlueTec en­gine has all the fea­tures of cur­rent diesels tech­nol­ogy, such as four valves per cylin­der, third- gen­er­a­tion com­mon- rail di­rect in­jec­tion, tur­bocharg­ing with a vari­able noz­zle tur­bine and ex­haust gas re­cir­cu­la­tion. And just like many cur­rent EU4 emis­sions- com­pli­ant turbo- diesels, this BlueTec en­gine fea­tures an ox­i­dis­ing cat­alytic con­verter, which re­duces emis­sions of car­bon monox­ide and un­burned hy­dro­car­bons, as well as a par­tic­u­late fil­ter. How­ever, what is spe­cial about this en­gine is a nitro­gen ox­ides stor­age cat­alytic con­verter, which when com­bined with an ad­di­tional ‘ Se­lec­tive Cat­alytic Re­duc­tion’ cat­alytic con­verter, slashes nitro­gen ox­ides emis­sions.

The Vi­sion C 220 BlueTec has a power out­put of 125kW and a peak torque fig­ure of 400Nm but uses only 5.5L/ 100km, and Mercedes claims the tech­nol­ogy is so clean that it will soon be ready to com­ply with tough EU6 emis­sion reg­u­la­tions, which are not en­forced in Europe un­til 2015.

A per­sua­sive so­lu­tion for CO re­duc­tion is the hy­brid, as most em­ploy an elec­tric mo­tor for the short trips with the added con­ve­nience of an on- board bat­tery charg­ing sys­tem for the longer trips that bat­tery re­serves alone will not sus­tain. The most re­cent de­vel­op­ment comes from Gen­eral Mo­tors, who cre­ated and sub­se­quently aban­doned its EV- 1 elec­tric car trial 11 years ago. GM has made a cau­tious re­turn to elec­tric cars with its Chevro­let Volt con­cept. GM has sig­nalled it is se­ri­ous about putting a ver­sion of Volt into pro­duc­tion — its first elec­tric- mo­tor mo­ti­va­tion, in­ter­nal com­bus­tion en­gine- as­sisted hy­brid.

The Volt uses GM’s E- Flex plat­form, a chas­sis specif­i­cally de­signed to ac­com­mo­date elec­tric ve­hi­cle com­po­nents. While GM calls it an elec­tric ve­hi­cle, it is ac­tu­ally a se­ries hy­brid — it has a tur­bocharged, 1.0- litre three­cylin­der en­gine that acts as a gen­er­a­tor charg­ing the Lithium Ion bat­tery pack. A 120kW elec­tric mo­tor drives the Volt and the bat­tery is charged by plug­ging it in to any stan­dard do­mes­tic out­let and is fully charged in about 6 hours.

The Volt will travel 60km on bat­tery power but if fur­ther travel is needed and there is no time to hook up to mains power, the Volt has a range of more than 1000km when its en­gine au­to­mat­i­cally starts and sup­plies charge to the bat­ter­ies. If driven for 35,000km an­nu­ally, and charged on mains power ev­ery night, GM claims that the Volt will re­duce CO emis­sions over a car that achieves 10L/ 100km by 4.4 met­ric tonnes.

GM be­lieves that flex­i­bil­ity is needed for cars like Volt, as the dic­tates of a par­tic­u­lar mar­ket re­quire. Ac­cord­ingly, GM has de­signed the Volt plat­form to cater for ethanol, hy­dro­gen fuel cell or pure bat­tery power.

The only thing that is hold­ing up GM’s first pro­duc­tion run is bat­tery de­sign. Once it finds a sat­is­fac­tory Li- Ion bat­tery pack — and can ob­tain enough vol­ume to sup­ply the pro­duc­tion lines — then it ap­pears Volt will be set for mass pro­duc­tion.

While GM’s hy­brid is an im­prove­ment of tech­nol­ogy al­ready avail­able, no one has pro­duced a sig­nif­i­cant zero- emis­sion car — the clos­est per­haps was the ill- fated GM EV- 1 of 1996. Elec­tric cars typ­i­cally have a short range be­fore the bat­tery runs out of power. It presents no prob­lems for short- haul use but for the tour­ing abil­ity re­quired by most car own­ers, the headache has been how to get bat­tery- power elec­tric cars to drive with­out long recharge times.

The US com­pany Tesla Mo­tors may be the first to go close to solv­ing this prob­lem when its bat­tery- pow­ered $ US98,000 sports car goes on sale later this year. The Tesla Road­ster is pow­ered by a lithium- ion bat­tery pack that Tesla Mo­tors claims is its big­gest in­no­va­tion, al­low­ing the Road­ster a range of 300km and a su­per­car- like 0- 100km/ h ac­cel­er­a­tion time of 4 sec­onds. It also claims the bat­tery pack will last up to 160,000km and is re­cy­clable. The Road­ster re­lies on mains power ( and to a small de­gree, re­gen­er­a­tive brak­ing, where the car’s brakes feed elec­tric­ity back into the bat­tery) and Tesla claims af­ter a 160km drive the bat­tery back will re­plen­ish af­ter only two hours of charg­ing.

The Tesla Road­ster may be this year’s most sig­nif­i­cant au­to­mo­tive tech­nol­ogy break­through. While Tesla claims it has con­ducted Road­ster dura­bil­ity tests with no ma­jor is­sues, the global au­to­mo­tive in­dus­try will be watch­ing very closely to see if the Tesla ex­per­i­ment works.



Twin­charger: Volk­swa­gen has mar­ried two well- known per­for­mance tech­nolo­gies

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