VWGoA - Ex. 1003
`Volkswagen Group of America, Inc. - Petitioner
`
`1
`
`

`
`VUICI I IQLIVCH l(l l"_-lJ
`
`Hybridfahrzeug
`
`Der Audi duo — des erste
`serienm£'iI3ige Hybridfahr eug
`
`Von Franz-Josef Paefgen
`und Marius Lehna
`
`Blid 1: Dle Technik des Audi duo
`
`Fig. 7: Sketch of the Audi duo
`
`Als F?esu/tat einer Entwicklung Uber mehrere Fahrzeuggenera-
`tionen bringt Audi nun ein Hybridfahrzeug in Serie. Dieses kann
`wah/weise mit einem E/ektromotor oder von einem TurbodieseI—
`
`motor mit direkter Einspritzung betrieben werden. Derzeit gibt es
`zum Verbrennungsmotor keine Alternative, die auch nur anne-
`hernd die gewohnten Fahr/eistungen und Fieichweiten bietet.
`Das Hybridautomobil ste/It jedoch eine Lo'sung dar, die vom
`Fahrer kaum Umgewohnung verlangt und dennoch Innerhalb
`von Stéidten _und Siedlungen ein emissionsfreies und geréusch-
`armes Fahren ermoglicht.
`
`1 Elnleilung
`
`1.1 TDI mit Biodiesel
`
`1.2 Erdgas
`
`Im heutigen gesellschaftlichen Umfeld ist
`das Auto als Mittel derindividuellen Mo-
`bilitét unverzichtbar [1]. Auflerdem spielt
`es zur Darstellung von Status und Lebens-
`einstellung eine wesentliche Rolle. Viele
`Entwicklungen in der Automobilindustrie
`zielen darauf ab. die Auswirkungen des
`motorisieiten Individualverkehrs auf die
`
`Umwelt mbglichst gering zu halten. Da-
`bei gibt es verschiedene Ansiitze, die zu
`prufen, zu erproben und zu vergleichen
`sind. Als Antriebssysteme sind derzeit fol-
`gende Alternativen vorstellbar.
`
`Die Verwendung von Pflanzen61meihyl-
`ester gehtirt heute zum Stand der Technik.
`Die Qualitét des alternativen Kraftstoffs
`ist in der Vornorm DIN V 51606 gercgclt.
`Im Vergleich zum herkijmmlichen Diesel-
`kraftstoff werden die Emissionen Von Par-
`tikeln, Kohlenwasserstoffen und Kohlen—
`monoxid reduziert, wéhrend eine leichte
`Zunahme an Stickoxiden hingenommen
`werden mull. Die zur Verfiigung stehen-
`den Anbaufléchen erlauben die Substitu-
`Lion eines nur geringen Anleils an petro-
`chemischen Kraftstoffen durch Biodie—
`Se] [2].
`
`Der Verbrennungsmotor mit Erdgas bie-
`tet beziiglich der CO2-Emissionen zwar
`Vorteile im Vergleich zu Benzin. erreicht
`jedoch nicht die giinstigcn Werte des Tur-
`bodieselmotors mit direkter Einspritzung.
`Fiir eine brauchbare Reichweite benétigt
`Erdgas ein zu grofles Tankvoiumen. Auch
`die cntsprechende Infrastruktux‘ zur
`fléchendeckenden Versorgung fehlt noch.
`Erdgas stellt deshalb fin‘ Automobile kei-
`ne befiriedigende Losung dar, bietet jedoch
`Chancen fur Nutzfahrzeuge. die regel-
`miiflig zu einem Tzmkdepot zurt‘ickkeh1'e!1
`kénnen [3].
`
`2
`
`ATZ Automobiltechnische zenschnn 99 (1997) 6
`
`2
`
`

`
`3
`
`

`
`Alternativamrieb
`
`Hybridfahrzeug
`
`rentialsperre stehen ebenfalls uneinge-
`schréinkt zur Verfiigung. Eine k1'afts1off-
`betriebene Zusatzheizung sorgt da fill‘, (.133
`auch beim Einsatz als Elektrnfahrzeug der
`Innenraum beheizt und die Scheiben be-
`schlagfrei gehalten werden.
`
`2.2 Barteriesystem
`
`Die Auswahl cles Batzeriesystems bestimmt
`lelztlich das ganze Konzepl, dem das Bab-
`tcriesystem hat maflgcblichen Einflufl auf
`die erzielbare Reichweite und die instal-
`
`lierbare Motorleistuog sowie auf das Ge-
`samtgewicht. die Fahrleistungen und den
`Preis des Fahrzeugs. Da der duo als Seri-
`enfahxzeug angebolen werden soll, ist auch
`die Frage nach der Serientauglichkeit von
`grofler Bedeutung. Um das optimale Bat-
`teriesystem auszuwahlen, wurden die ver-
`fflgbnrcn Konzepte nach den Kritcrien
`Energiedichte. Leistungsdichte, Betrieb-
`stemperatur, Lebensdauer, Sicherheit, Um-
`weltvertréiglichkeit, Preis und Stand der
`Technik verglichen. Die wichtigsten Daten
`der Systeme sind in Bild 3 dargestellt.
`
`Von den roch in Entwicklung befindlichen
`Batteriel". scheiden fur dlesen Anwen-
`dungsfall die Natrium-Nickel—Ch1oridbat—
`terie wegen ihrer hohen Betn'ebstempe1°a-
`lur und die Zink—Brom-Batterie wegen zu
`geringer Leistungsdichte und Wu'kungs-
`grad aus. Vielversprechend stellen sich hin-
`gegen das 1\fickel-Meta]]hyrlrid—System so-
`wie die Lithium-Batterie dar. Diese Kon-
`zepte wetden weiterhin verfolgt und auch
`im praktischen Einsatz erprobt. Unter den
`beneits serientauglichen Systemen zeichnet
`sich die Nickel-Cadmium-Batterie (lurch
`hohe Leistungs- und Energiedichte aus. Sie
`kommt jaioch wegen der Verwendung von
`Cadmium nicht in Frage.
`
`Somit stehen als Serienprodukte derzeit
`mu‘ Bleibatterien zm‘ Verfugung. Diese
`bieten ejne Reihe von Vorteilen: War-
`tungsireiheit, niedrige Bet1'iebstempera—
`tut. gute: Lade— und Entladewirkungs-
`grad SOWIB gfinstiger Preis. Bei der im duo
`eingesetzten Blei-Vljes-Batterie ist der
`Elektrolyt. in ciner Vliesmatte gebunden,
`
`Der Audi duo is! als Parallelhybrid aus-
`gefiihrt. Der Antrieb wird also entweder
`durch das 'I‘urbodiesel- oder das E1ekt.ro-
`Aggregat erzeugt. Beide Aggregate arbei-
`ten unabhfmgig voneinander. Dies bietet.
`im Elektroantrieb den Voxteil. dafl er vor
`Ort volllg emlsslonsrrel becrleben werden
`kann.
`
`2.1 Baslsfahrzeug
`
`Ausgangsbasis fur den duo ist der Audi A-1
`Avant mit I-‘rontantrieb und Vie1'zy1inder-
`'I‘urbodiese1moto1' mit direkter Einsprit-
`zung (66 kW). Dieser Antlieb gilt hin-
`siclltlich Leislung und Sparsamkeil als
`vorbildlich und kann selbstverstfindlich
`auch mit Pflanzenolmethylester betrieben
`werden. Der TDI-Motor is! fiber eine kon—
`ventlonelle Einscheiben—Trockenkupp-
`lung mit dem Ffinfgang—Schaltgetriebe
`verbunden. Allerdings schaltet der Fahret
`ohne Kupplungspedal, da ein hydrauli-
`sches Kupplungsmanagement fur auto-
`matisches Kuppeln sorgt.
`
`Das Basisfahneug wird um einige fin’ den
`duo spezifische Umféinge ergénzt. Dazu
`gehort unter anderem die Batterlewanne
`anstelle den‘ Reserveradmuldc und ver-
`schiedene Aufnahmen ifir die zuséitzliche
`Elektronik. Das hohere Fahrzeuggewicht
`wurde naturlich bei der Auslegung und
`Abstimmung Von Fahrwerk und Bremsen
`berucksichtigt Mit der Verwendung die-
`ses Serienfahrzeugs ist sichergestellt, dafl
`keine Kompromisse hinsichtlich Fahr-
`eigenschaften, Sicherheit, Reichweite,
`Raumangebot. und Komfort gemacht wer-
`den. Der Fahxzeuginnenraum wird dutch
`die zusétzlichen Komponenten praktisch
`mcht beeintrfichtigt. Die Verénderung im
`Laderaum ist nur bei direkter Gegen-
`iiberstellung mit dem herkommliehen
`Fahrzeug erkennbar. Der Kraftstoff-
`behélter wurde auf ein Volumen von 42
`Liter verkleinert.
`
`Zur Beibehaltung der Lenkkraftunter-
`stiitzung wird ein elektrohydraulisches
`System eingesetzt. Bremsservo, An-
`tiblockiersystem und elcktronischc Diffe-
`
`wodurch auch bei Unfaillen keine Sam-9
`auslauten kann. Auch das bereits eta-
`blierte vollsténdige Recycling von Bleibat.
`terien stellt einen entscheidenden Plus.
`punkt dar. Das ausgewéihlte Batterieele.
`ment besteht aus 22 in Reihe geschalteten
`Modulen und ist in einer Wanne unter deg-
`Ladeflfiche uutergebracht. Es liefert 234
`V Spannung und 10 kWh Kapazitét. Dies
`entspricht im Stadtverkehr — je nach
`Fahrweise — einer Reichweite von bis zu
`50 Kilometern.
`
`Ein Batte1'ie—Management—System (BMS)
`tibemimmt die Steuerung und Uberwa-
`chung aller Lade- und Entladevorgangg
`I-Iierzu werden stfindig Daten von allen 22
`Modulen gesammelt und verarbeitet. Mit
`BMS wird die Batterie geschont. wodumh
`sich eine lfingere Lebensdauer e1'gibt_
`Trotz der hohen Belastung der Battcrie in
`einem I-Iybridantrieb gehen wir von einer
`Lebensdauer von mindestens drei Jahren
`fiir (lie Batterien aus.
`
`!
`
`Im Kombiinstrument wird permanent der
`aktuelle Ladezustand der Batterie ange-
`zeigt, so daB der Fahrer jederzeil. ablesen
`kann. wann nachgeladen werden mm}.
`Das Aufladen kann an jeder haushaltsiib-
`lichen Steckdose erfolgen, wobei die Ver-
`wendung preiswerten Nachtstroms be-
`sonders sinnvoll ist. Das Ladekabel ist. un-
`trennbar mit dem Fahrzeug verbunden.
`Snlange es mi! einerstromquelle verhun.
`den ist, kann das Auto nicht gesta1'tetwer..
`den. Auch die beim Bremsen freiwerden-
`de Energie wlrd zum Laden der Batterie
`genutzt. Der Elektromotor arbeitet dann
`ebenso wie im TDI—Betrieb als Generator.
`
`2.3 Elektromotar
`
`Bereits bei der Konzepterstellung wulde
`kiar, daB ein den Ansprilchen genfigender
`Elektromotor nicht auf dem Mark! ver-
`mgbar war. Deshalb entschied man sich,
`eine neue Maschine zu entwickeln. die in
`Zusammenarbeit mit der Universiuit
`Leoben und der Firma Siemens realisiert
`wurde. Es handelt sich um eine perma-
`nenterregte Synchronmaschine, die mit
`
`Blld 3: Verglelch der
`Balterlesysteme
`
`Fig. 3: Comparison of
`battery systems
`
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`ATZ Automobiltechnische Zeitschrift 99 (1997) 5
`
`4
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`Alternahvantneb
`Hybridfahrzeug
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`Bild 4: Prlnzipdarstellung des Antrlebsstrangs
`
`Hg. 4: Skerch of the drive train prlnclple
`
`Soilwalgebet
`
`Uimichlar
`
`Molar
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`Banerlcp
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`
`Bild 5: Regelstruktur der Antrlebssteuerung
`
`Fig. 5: Sketch of the drive train management
`
`
`
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`Swsom
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`Pulpherie
`
`Gosczggndlgv
`
`Wasser gekfihlt wird. Sie zeichnet sich
`dutch gute Wirkungsgrade im Tei1— und
`Uberlastbereich, hohe spezifische Lei-
`stung, groflen Drehzahlbereich. geringes
`Gewicht, niedrigen Platzbedarf, fabr-
`zeuggerechte Konstmktion sowie Ver-
`schleiI3- und Wertungsfreiheit aus. Alle
`diese Kriterien werden bei vertretbaren
`Kosten erfflllt.
`
`Mi! einem Gewicht von nur 22 Kilogramm
`leistet der Elektromotor 21 kW‘ Er ist
`
`kurzfristig bis 35 kW iiberlastbar und er-
`reicht ein Drehmoment von 20 Nm. Der E-
`Motor arbeltet mit maximal 10000 Um-
`drehungen pro Minute. Das in des Genie-
`begehéuse integrierte sogenannte Varga-
`lege paflt diese Drehzahl den Anforde-
`rungen des Antriebsstrangs an, Bild 4. Da
`der Elektromotor auf die Gctriebeein-
`gangswelle wirkt, kann det Fahrer auch
`im Elektroantrieb alle Gfinge des Getrie-
`bes nutzen.
`
`2.4 Betriebswahlschalter
`
`Der Audi duo bietet dem Fahmr drei Be-
`triebsmtiglichkeiten, die er an einem
`Schaltcr in dcr Mittclkonsole anwiihlen
`kann:
`1. Nu Dieselmotor
`2. Nut‘ Elektrobetrieb
`3. Hybridamrieb.
`
`Beim I-Iybridantrieb erfolgt der Wechsel
`der Antriebsarten automatisch je nach
`Anforderungen des Fahrbetriebs. Fm'1an-
`ge Strcckcn wird normalerwcisc aus-
`schliefllich der Dieselmotot benutzt. Be-
`wegt man sich in Gegenden, wo her-
`kémmlich angetriebene Fahrzeuge stéren
`oder nicht zugelassen sind.1EiBt sich auf
`reinen Elektrobetrieb schalten.
`
`Die Normalstellung, die nach dem Start
`automatisch aktiv ism, reprasentiert den
`Hybridantricb. Jc nach Anforderungen des
`Fahrbetriebs w'u'd vollautcmatisch zwi-
`schen Elektro— und Dieselantrieb gewech-
`selt. Bis zum Kick-Down-Punk! fiber-
`nimmt die Synchronmaschine den Antnieb.
`Durch kréftiges Gasgeben wird dann ruck-
`frei auf den Dieselmotor umgeschaltet. Im
`Stadtverkehr, insbesondere im Stop-and-
`Go. kommen die Vonelle des Elektroan-
`tricbs voll zum Tregen, derm dieser be-
`nétigt nur dann Energie. wenn das Fahr-
`zeug auch tatséichlich bewegt wird.
`
`Die Einbindung eines zusiatzlichen An-
`triebs in ein vorhandenes Fahrzeug erfor-
`dert eine komplexe Antriebssteuerung, die
`in Bild 5 dargestellt ist.
`
`3 Fahrleisrungen
`
`Im Dieselbetrieb erreicht der duo §hnli—
`che Fahrleistungen wie das Basisfahrzeug.
`Die Hiichstgeschwindigkeit betréigt 170
`km/h, fiir die Beschleunigung Von 0 - 100
`km/h vergehen etwa 16 Sekunden. Im
`
`Elektrobetrieb 1581: sich der duo in 9,5 Se-
`kunden von 0 - 50 km/h beschleunigen; die
`Hfichstgeschwindigkeit von 80 km/h wird
`elektronisch begrenzt. um ungewolltes
`Entladen der Batterie bei Uberlandfahw
`ten zu vermeiden. Die Reichweite mit dem
`Dieselmotor betrégt mehr als 700 Kilo-
`meter. im Elektrobetrieb kann etwa 50 Ki-
`lometer weit gefahren wexden.
`
`4 Ganzheltllche Betrachtung
`
`Em Fahrzeug mit zwei Antrieben ist
`zwangsléiufig schwerer als ein herk6mm—
`liches. Da ein im Kraftstoffverbrauch
`fiihrendes Basisfahrzeug gewéhlt wurde
`und die Komponenten fin‘ den Zweit.an—
`tricb so leicht wie méglich gchalten Wur-
`
`ATZ Automobillechnische Zeitschrift 99 (1997) 6
`
`319
`
`5
`
`

`
`6
`
`

`
`
`
`utomotive Engineering Journal
`
`Research, Development, Construction, Testing and Production
`
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`Brake Electronics in
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`Commercial Vehicles
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`Audi duo -The First Serial-
`
`Production Hybrid Vehicle
`
`.
`
`
`
`7
`
`

`
`nu. 1-up canny. guunuxruaq
`
`Alternative Drive
`
`Hybrid Vehicle
`
`The Audi duo - The first Serial-
`
`Production Hybrid Vehicle
`
`Image 1:1heleclmlogyonneAuaiauo
`
`Fig. 1: Sketch of the Audi duo
`
`By Franz-Josef Paefgen
`and Marius Lehna
`
`As the result of development work spanning multiple vehicle generations Audi
`is currently introducing a hybrid vehicle into serial production. It can optionally
`be operated by an electromotor or a turbo diesel engine featuring direct
`injection. At present, there exists no altemative to the combustion engine that
`comes even close to offering the usual driving performance and ranges.
`However, the hybrid automobile represents a solution that requires barely any
`readjustment on the part of the driver, yet still allows emission-free and low-
`noise driving within cities and populated areas.
`
`Introduction
`
`1.1 TDI using bio-diesel
`
`1.2 Natural Gas
`
`In the current social environment. the car
`as a means of personal mobility is
`indispensable [1]. Moreover. it plays an
`essential role in the display of status and
`lifestyle. Many developments in the
`automotive industry focus on minimizing
`the effects of motorized personal driving
`on the environment. There are a number
`
`of approaches that have to be examined,
`tested and compared. The following
`alternatives are currently conceivable as
`drive systems:
`
`The use of plant oil methyl ester is
`currently part of the state of the art. The
`quality of the alternative fuel is regulated
`in the prestandard DIN V 516606.
`Compared to conventional diesel fuel, the
`emissions of particles, hydrocarbons and
`carbon monoxide are reduced. while a
`slight increase in nitrogen oxides is
`allowed. The available cultivable land
`
`allows only a small portion of
`petrochemical fuel to be replaced by bio-
`diesel [2].
`
`316
`
`The combustion engine using natural gas
`offers advantages over gasoline with
`
`regard to the CO2 emissions, but does not
`attain the advantageous values of the turbo
`diesel engine featuring direct injection. The
`tank volume required for natural gas is too
`large to achieve a practical range. Also. the
`corresponding infrastructure for an
`uninterrupted supply is still missing. Natural
`gas thus does not constitute a satisfactory
`solution for automobiles but offers chances
`
`for commercial vehicles that can regularty
`return to a fuel depot [3].
`ATZ Automobilteclmische Zeitschrilt 99 (1997) 5
`
`8
`
`

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`]
`
`Noticeable improvements can be achieved
`only by concepts that can be Used in
`corresponding vehicles of the current
`standard. We therefore consider it useful to
`combine the combustion engine with an
`electric drive. For one, this makes it possible
`to drive in cities and populated areas in an
`emission—free manner, and the mobility
`when driving long distances is ensured for
`another. The hybrid vehicle Audi duo shown
`in Image 1 represents the first variant of this
`idea that is ready to go into production.
`
`.
`.
`Electric Dnve
`1'4
`The possibilities of the electric drive
`depend to a decisive degree on the
`availability of suitable batteries. At
`present, no batteries are offered by which
`2 Technicai Description of the
`an automobile could be operated while
`maintaining the usual driving performance Audi due
`and a similar range.
`
`13
`
`Hydrggen
`
`l
`I
`I
`
`In fuel cells, the chemical energy of a
`combustion reaction is converted directly
`‘
`into electric energy so that high electric
`efficiencies are achieved. Polymer
`electrolyte diaphragm fue| cells‘ which
`are characterized by high specific current
`density and a compact design. are used
`for the application in automobiles.
`
`1.5
`
`Hybrid Drive
`
`Based on this situation, there is obviously
`no alternative to the combustion engine in
`the foreseeable future. In our
`'
`'
`understanding niche solutions which
`cannot replace the conventional
`automobile but may be used in addition‘
`do not lighten the burden on the
`environment.
`
`Image 2 shows the long road of the Audi
`duo toward its readiness for series
`production readiness. As early as 1989,
`Audi presented a duo Oh the basis Of the
`Audi 100 Avahi QU€it1i0— iii 1991. the
`Secohd CIUO generation f0i Which
`.
`.
`.
`°°"‘F"9h9"5lV9 ‘e5““9 l” “'9 field ‘"35
`Camed °”‘ ”5'”9 5e'e°‘ed Veh'°'9 "595-
`was presented in completely revised form.
`Testing of the technology and an
`examination of its acceptance led to the
`development of the third generation and to
`the readiness for series production.
`
`ITM I170 ‘W3!!! llh
`
`ZTIW‘ WW 5111! fill!
`
`1991 Audi duo - Second generation
`
`1996 Audi duo - Third generation
`
`Ilsls Audi 100 Avant qimtro
`
`ATZ Automuhiltechnischo 7.eiLs'chi'ift E19 l1§i§l7l ll
`
`ge Entwick|ungs-
`schritte zum
`Serleneinsatz des
`duo
`
`Fig 2: Three important
`development steps
`towards series
`production of the duo
`
`BMW‘ 72% 1I.5|ID2|lI
`
` 1989 Audi duo - First generation
`
`Outs Audi ton Mam quamo
`
`Basis Audi A4 Avam
` Blld 2: Drel wlchtl-
`
`9
`
`

`
`The Audi duo is developed as a parallel
`hybrid. The drive is therefore generated
`either by the turbo diesel or the electric
`power unit. Both power units operate
`independently of each other. In an electric
`drive, this offers the advantage that it can be
`operated locally in a completely emission-
`free manner.
`
`2. 1 Basic Vehicle
`
`Starting basis for the duo is the Audi A4
`Avant with front wheel drive and a 4-cylinder
`turbo diesel engine featuring direct injection
`(66kW). This drive is considered exemplary
`from the aspect of perionnance and
`economy and may of course be operated
`using plant oil methyl ester as well. The TDI
`engine is connected to the fivegear
`transmission via a conventional single disk
`dry clutch. However, the driver shifts gears
`without using a clutch pedal since automatic
`gear shifting is provided by a hydraulic
`transmission management.
`
`The basic vehicle
`is 5“pp'e'“e"ted W Some
`content that is specific to the duo. Such are,
`for example, the battery tray instead of the
`spare wheel well,
`and various receptacles
`for additional electronics. The higher vehicle
`weight was of course taken into account in
`the configuration and adaptation of the
`undercarriage and brakes. The use of this
`series-produced vehicle ensures that no
`compromises are
`made with regard to
`driving performance, safety, range, offered
`space and comfort. The passenger
`compartment is virtually unaffected by the
`additional components, The change in the
`cargo space is noticeable only in a direct
`comparison with the conventional vehicle.
`The fuel tank was reduced to a volume of 42
`liters.
`
`A hydraulic system is employed in order to
`retain the power steering. Power brakes,
`antilock braking system and electronic
`differential lock are likewise fully available.
`
`Alternative Drive
`
`Hybrid Vehicle
`
`A fuel-driven supplementary heating system
`ensures that the passenger compartment is
`heated even when electric driving takes
`place and that the windows are kept
`defogged.
`
`2.2 Battery System
`The choice of battery system ultimately
`defines the entire concept because the
`battery system has a decisive effect on the
`achievable range and the installable engine
`power as well as the total weight, driving
`performance and the price of the vehicle.
`Since the duo is meant to be offered as a
`series-produced vehicle, the question of its
`series suitability likewise is of particular
`importance. In order to select the optimal
`battery system, the available concepts were
`compared based on the criteria of energy
`density, power density, operating
`temperature, service life, safety,
`environmental compatibility, as well as price
`and state of the art. The most important data
`of the systems are shown in Image 3.
`
`Of the batteries still under development, the
`sodium nickel chloride battery is unsuitable
`for this particular application case because of
`its high operating temperature, and the zinc-
`bromide battery because of insufficient power
`density and efficiency. The nickel metal
`hydride system and the lithium battery, on
`the other hand, are very promising. These
`concepts are under further consideration and
`have also been tested in practical use.
`Among the systems that can already be used
`in a series production, the nickel cadmium
`battery stands out due to its high power and
`energy densities. However, it cannot be used
`because of its use of cadmium.
`
`Thus, only lead batteries are currently
`available as series product. They offer a
`number of advantages: no service
`requirement, low operating temperature,
`excellent charge and discharge efficiencies,
`and a cost-effective price,
`
`In the lead-fleece battery used in the duo the
`electrolyte is bound in a fleece mat, which
`prevents acid from leaking even in the event
`of an accident. The already frrrnly established
`complete recycling of lead batteries also
`constitutes a decisive advantage. The
`selected battery element is made up of 22
`modules connected in series and is
`accommodated in a well underneath the
`cargo space. It provides a voltage of 264V
`and a capacity of 10 kWh. This corresponds
`to a range of up to 50 kilometers in city
`driving, depending on the driving style.
`
`The battery management system (BMS) is
`in charge of control and monitoring all
`charge and discharge operations. Data
`from all 22 modules is collected and
`processed on a continuous basis for this
`
`purpose. The use of BMS is gentle on the
`battery and thereby results in a longer
`service life. Despite the high loading of the
`battery in a hybrid drive, we assume a
`service life of at least three years for the
`batteries.
`
`‘
`r
`‘
`.
`
`The actual charge state of the battery is
`constantly displayed on the instrument
`cluster, so that the driver can always see
`when recharging must take place. Any
`conventional household outlet may be used
`for the charging operation, and the use of
`the less expensive off-peak power is useful.
`The charge cable is permanently connected
`to the vehicle. As long as it is connected to
`a power source, the car is unable to be
`started up. The energy released during a
`braking operation is also utilized for
`charging the battery. The electric motor
`then operates as a generator, as is also the
`case in a TDI operation.
`
`2.3 Electromotor
`
`Even when the concept was under
`development, it became clear that an
`electromotor that satisfied the demands was
`not available on the market. It was therefore
`
`decided to develop a new machine, which
`was developed in cooperation with the
`Leoben University and the Siemens
`corporation. It is a pennanently excited
`synchronous machine which is cooled by
`
`I
`
`‘
`.
`
`l
`‘
`
`'
`
`Operating
`Temperature
`Range (‘Cl
`
`Cliarge and
`Discharge
`Degre
`
`Service Life
`(ryclesl
`
`Cost '
`
`rrrwmrwru
`
`Develovmem
`S““”*
`
`Blld 3: Verglelch def
`Balterlesysteme
`Fig. 3: Comparison of
`battery systems
`
`Series Product
`
`Series Product
`
`
`
`Prototype
`
`Prototype
`
`
`
`0 MD
`
`I
`* Egfgnated [of >t.00D SLIJ-hr bel Slrlnnprndnktirrrr
`
`a "Hill
`
`Rllll
`
`Prototype
`
`318
`
`ATZ Automobrltechnische Zeitschrift 99 (1997) 5
`
`10
`
`En‘?fl.lY D€T|S|1Y
`lW"""-:l
`
`Power Density
`
`llmrrgr
`_
`
`Battery Type
`
`LearJ»Flr;-ece
`
`Nluul-Crmrmrrrn
`
`NICKEL
`Metallhvrlrrde
`
`Natr|um—Nrcke|—
`CIIIDIILIF:
`
`Zrnk—Bromrne
`
`Lirhrtrnil-Jri
`
`10
`
`

`
`Alternative Drive
`
`Hybrid Vehicle
`
`Schematic diagram of the Audi du
`
`0 drive train
`
`water. It is characterized by excellent
`efficiencies in the partial and overload range,
`high specific performance, large rpm-ranges,
`low weight, a low space requirement, vehicle-
`appropriate construction and no wear and
`service requirement. All of these
`requirements are satisfied at reasonable cost.
`
`I I
`
`With a weight of only 22kgs, the electromotor
`r generates 21kW. Brief overloading to up to
`r 35kW is possible and achieves a torque of
`I 20Nm. The Emotor operates at maximally
`I 10,000 revolutions per minute. The so—called
`r
`reduction gear, which is integrated into the
`' gear box housing, adapts this engine speed
`0
`to the requirements of the drive train, Image
`' 4. Since the electromotor is acting on the gear
`input shalt, the driver is able to use all gears
`of the transmission even while operating in
`the electric driving mode.
`
`Blld 4: Prlnzlpdarstellung des Antrlebsstrangs
`.
`-
`-
`~
`Fig. 4. Sketch of the drive train principle
`
`fiififlfi’
`
`C23’
`
`Motor
`
`Brie
`
`Susy
`Drive Sensor
`
`Batty
`W50‘
`
`51''“,
`cmunr
`
`Hi iii
`Tangerine
`
`2.4 Operating Mode Selector Switch
`
`l ‘
`
`' The Audio duo offers three potential operating
`1 modes to the dmer which are Selectable with
`the aid of a switch in the center console:
`1. Diesel engine exclusively
`' 2. Electric operation exclusively
`' 3. Hybrid driving mode.
`In the hybrid driving mode, the switch between
`the drive modes occurs automatically,
`depending on the requirements of the driving
`operation. For longer distances, it is generally
`the diesel engine that is used exclusively. A
`
`i switch to pure electiic driving is possible when
`I traveling in areas where vehicles equipped
`V with a conventional drive would pose a
`| nuisance or are banned.
`
`The normal setting that is active automatically
`1 following the startup represents the hybrid
`drive. Depending on the requirements of the
`driving operation, a fully automatic switch
`. takes place between electric and diesel drive.
`' The synchronous machine assumes the
`' driving up to the kick—down point, and a switch
`.' to the diesel engine is then accomplished by a
`forceful acceleration. In city driving, in
`
` advantages of the electric drive fully take
`
`l effect, because energy is then required only
`when the vehicle is actually in motion.
`
`particular in storrand—go driving, the Bfihlycllrul
`
`L"-flVfins
`
`nan-yvuaoeu-a
`“"5
`I
`ndruyllurqu
`
`*
`.
`‘hmurutclrrnun
`
`4 Overall Evaluation
`
`A vehicle having two drives is inevitably
`heavier than a conventional vehicle. Since a
`basic vehicle was selected that ranks at the
`
`top as far as consumption is concerned, and
`since the components for the second drive
`were kept as light as possible,
`
`11
`
`| The incorporation of an additional drive into an
`' existing vehicle requires a complex drive
`i control, which is illustrated in Image 5.
`
`End 5: Regelstruktur der Antrlebssteuerung
`
`Fig. 5: Sketch of the drive train management
`
`In an electric operation, the duo can be
`accelerated from 0 to 50krn/h in 9.5
`
`seconds; the maximum speed of 80kmIh is
`electronically restricted in order to avoid
`unintentional discharging of the battery in
`Iong—distance driving. The range for the
`diesel engine amounts to more than 700
`kilometers, while approximately 50
`kilometers can be driven in the electric
`
`driving operation.
`
`31 9
`
`3 Driving Perfonnance
`In the diesel operating mode, the duo
`achieves a similar driving performance as
`the basic vehicle. The maximum speed is
`170kmIh, and approximately 16 seconds
`
`r I H
`
`I
`
`‘ elapseinanaccelerationfrom0to100knr/h.
`
`ATZ Automobiltechnische Zeitschrift 99 (1997) 6
`
`11
`
`

`
`higher power utilization will come about in
`Gennany as well. Ideal for the duo is the
`refueling using solar energy, as it is
`practiced on Audi's factory premises.
`
`5 Summary
`
`According to the current state of the art,
`which does not offer adequate battery
`systems for pure electric vehicles, a hybrid
`drive of the type used in the Audi duo
`constitutes the best possible compromise.
`It offers both the usual mobility over long
`distances and emission—free driving in an
`electric driving mode. In addition, it is not
`necessary for the driver to adjust to the
`handling characteristics or to forego safety '
`or comfort. This makes the Audi duo an
`ideal vehicle for use in emission-sensitive
`
`regions. Once market readiness has been
`achieved, the duo can be offered as a
`series-produced vehicle at the end of
`1997.
`
`Alternative Drive
`
`Hybrid Vehicle
`
`Consumption and CO2 emissions of the Audi A4 Avant TDI and the Audi duo
`
`European driving cycle (93.’116/EWGl
`37% cityl 63% long distance
`
`duo driving cycle
`70% city. 30% long distance
`
`rm itv mt Amt: 'l|iv:
`H’):
`
`A4 ALAI‘,'
`‘fir
`
`(turf Mu
`
`l1I\Au.1n' Qurti mm A4 A\i..ru ilnim mm
`TDI
`Tr)!
`
`"r.;'-:;;1V:1'.'.t_.'
`
`‘I 3.
`
`F‘
`
`E RC ENT AG ES/ %
`
`Bild 6: Verbrauch und CO,- Emlsslonen des
`
`Audi duo und des A4 Avant TDI
`
`Fig. 6: Consumption and CO2 emissions for the Audi A4 Avant TDI and Audi duo
`
`Literaturhlnweise
`
`,'
`
`respectable values have been obtained as
`an overall result. When comparing the
`consumption and the CO2 emissions of the
`Audio A4 Avant TDI and the duo, the duo
`has the advantage both in the European
`driving cycle and in a driving cycle which
`features a higher city component that was
`adapted to the purpose of the duo. Image
`6.
`
`In general, power plants have better energy
`efficiency than mobile combustion engines.
`The exhaust gas purification on a large scale
`can be carried out more efficiently as well.
`When using current “from the socket", the
`utilization factor of the power-generating
`plant and the specific power plant
`combinations used in the respective country
`constitutes the decisive variable. Within the
`framework of the holistic balancing generally
`undertaken by Audi, the energy expenditure
`in connection with the manufacture, the
`driving operation and recycling was
`ascertained for the duo as well [5].
`
`With the increasing modernization of power
`plants and greater use of regenerative
`energy sources,
`
`The Authors
`
`Bild 7: Kumullerter
`Energieverbrauch
`des Audi duo fur
`verschledene Lan-
`der
`
`Fig. 7: Total energy
`consumption of the
`Audi duo for different
`.
`countries
`
`Dr. Franz-Josef Paefgeir
`is a boaid member for the
`technical development
`business area, and
`designated chainnan of
`the board of the Audi
`
`GmbH.
`
`Marius Lehna is the
`spokesman of the Hybrid
`Drive Expert Gmup at
`Audi GinbH.
`
`fj.
`
`'[
`
`12
`
`ATZ Automnbiltechnischc Zeitschri ft 99 (1997) 5
`
`320
`
`Deuaufmhniul
`supptydhushr
`aunt:
`
`rim
`
`Audi A4 TDI Avant
`
`hm '
`
`AM, duo
`in duo
`driving
`Gide
`
`—
`‘Ne
`Gemrarly
`
`my
`Austria
`
`l
`.
`i
`
`
`
`0
`
`20
`
`40
`
`60
`
`80
`
`100
`
`120
`
`In the same way it was examined how the
`type of current supply in different countries
`affects the vehicle operation, Image 7. While
`the extra expenditure cannot be recouped
`completely in Germany, a balanced balance
`sheet results for Italy. One clear advantage
`of the duo is illustrated based on the power
`plant mix of Austria, for example, where the
`energy savings amount to roughly 20%. A
`daily driving distance of 70 kilometers with
`10 years of use and a distance split between
`city and long distance travel of 70 to 30
`fonns the basis of the calculations. This split
`conforms to the principle and purpose of the
`duo, since it is well known that more than
`70% of all driving involves travel of less than
`50 kilometers.
`
`I
`
`1
`
`I4]
`
`I5]
`
`I1) Gesellsclmft FahrzL-ug- und Verkehrsy
`technik: Der Mensch im Verkehr. Tagung,
`Miinchen, 30./3l.Januai 1997, Diisseldorl.
`VI}I—Ve1‘lag 199']
`TUV Bayern Holding AG: Biudiesel fttr
`Fahrzeuge, Mum-hen 199