Thread: Twincharging je Volvov nadomestilo za selitev

Downsizing motorja je vse bes. Izdelavo manjših motorja poveča izkoristek goriva, zmanjšuje emisije in kosi teža vozila. Z doslej zaostritev goriva gospodarstvo zakonodaje v ZDA in CO2 emisije uredbe Evropske unije, kopno proizvajalci obrača turbopolnilniki, kot še nikoli prej. V letu 2009 le 5 % avtomobile prodajajo v Ameriki sported turbos in da 5 % so sestavljali večinoma evropskih blagovnih znamk, kot Volvo in BMW z dolgo zgodovino kompresorski. Do leta 2013 ta številka več kot podvojil na 13 %. Honeywell pričakuje številko povečal na 25 % v naslednjih štirih letih in EPA mi pravi, da do leta 2025 pričakujejo 90 % avtomobilov, prodanih v Ameriki s športom turbo motor. Z turbos postal tako vsakdanji, kaj a turbo pionir kot Volvo ohraniti konkurenčno prednost? Seveda dodati polnilnikom.
Pred kratkim sem imel priložnost, da vzorec novi Volvo V60 (pričakujejo prvi pogon pregled kmalu) ampak zvezda večera ni bil sam avtomobil, njene kaj pod pokrovom. Nov motor modeli so resnično redkost v avtomobilskem svetu z motorji, ki tweaked da jih ohranja sveže. Volvov lastnih modularnih motor najdete pod pokrov največ švedskega avtomobilov (in občasno Focus RS) obrnil 24 let, letos, vendar je spomladi piščanca v primerjavi z Rolls Royce L serije 6. 75L motor, ki sega do 1952. Biti motor nerd, sem, sem preživel novo ur z Volvov pogonskih inženir razpravljamo njihovo novo družino motorjev pogon E.
Novi Volvov družine motorjev je predvsem odpustitev design, čeprav veliko oblikovanje komponente so potomci starih modularni motor družine. Linija vsebuje štiri različne variante, ki so ga poimenovali T3, T4, T5 in T6. Kot prej, T označuje Turbo ampak zdaj številka predstavlja moč namesto jeklenke v številu vključenih. Ja, to je smrt Zvoniti za Volvov funky 5-valjni, ker je to strogo štirivaljni Postrojavanje. Volvo je dejal 149 konjskih moči T3 in 188 konjskih moči T4 ne vodi v Ameriko v tem trenutku, zato ne pričakujem, da vidim neposredni konkurent BMWs krčenja 320i iz Švedske letos. Namesto tega smo dobili 241 konjskih T5 in 302 konjskih T6, pod pokrovom za vse razen za XC90.

Vsi motorji delijo skupno podobo blok, ampak kaj spremeni je zgorevanje. T3, T4 in T5 motorji uporabi ene turbo, medtem ko T6 dodaja korenine tipa polnilnikom poleg s turbopolnilnikom. VW in drugi so dabbled s twincharging v preteklosti, z VWs 1. 4L motor twincharged, ugotovitev a dom pod nape evro modeli in odlaganjem 140-180 konjskih moči. Volvo je ob stvari na naslednji korak s pozivom svoje 2. 0 L motor zamenjava za ne samo 3. 0L pomikanje twin turbo, ampak tudi pred kratkim odstopila 4. 4L V8.
Medtem ko polnjenja in turbopolnilnikom zveni pretirano, je logika za norost. Medtem ko vrha navor na turbo samo T5 samo 15 lb-ft nižja T6 (v overboost), s polnilnikom omogoča T6 raznašati približno 140 lb-ft več navora tik ob nedejavnosti. Krivulje navora konvergirajo okoli 1.500-1600 RPM, ko na T6 ranžirna lokomotiva nad v tem prihranijo. Od približno 2.000 RPM do 3500 RPM navora še ravno na obeh motorjev, vendar večje turbo na na T6 omogoča, da ohrani vrha navora vso pot mimo 4500 RPM. Ko navora začetek v zmanjkovati, je pa tako bolj postopno, kot samo za turbo motorji.

Zakaj ne držijo s polnilnikom, ki je sam kot Jaguar in druge avto oblikovalci? Razlog je dva-krat. Turbopolnilniki delujejo off odpadne energije iz izpušnih plinov. Izpušni plini spin turbine, ki pa vrti kompresor, silijo več zraka v motor. V resnici odpadne energije je napačno ime, saj je cestnina konjskih moči ker turbo posega v toku izpušnih plinov, vendar na splošno je ta davek manjša moč, potrebno za delovanje polnilnikom. Znano je negativna, da je turbo: turbo lag. Turbo lag je čas turbo za začeti Boos. Čeprav je turbo predenje na idle, njeno ustvarjanje malo tlaku. Pritisnemo na plin in traja nekaj časa za stvari za začetek brenčanje skupaj in povečanje ustvariti. Thats zakaj T5 je nižja ocena navora off nedejavnosti.
Superchargers so po navadi odpelje opremo pasu. Zaradi neposredne povezave z motorjem, so vedno ustvarjanje povečala. Ker to povečanje se zgodi v sinhronizacijo z motorjem RPM, je takojšen odziv. O določitvi strani superchargers lahko porabijo do 20 % izhodno Skupna moč motorjev glede Honeywell. To se šteje dober trgovine, saj lahko škorenj moči do 50 %. Zaradi oblikovanja trgovinske vzleti, tovarne, polnilnikom motorji ponavadi zmanjka sape na višjih RPM, ki pojasnjuje, zakaj jaguarji 5. 0L polnilnikom motor zaostaja 4. 4L in 4. 7L twin-turbo nemških motorjev s široko polje v vrh navora.
Volvov odgovor na obeh težav je rabiti a polnilnikom za takojšen odziv na nizko koncu. Iz stoječega zračnega tokov v s polnilnikom, nato pa skozi turbo v motor. To ne le izboljšuje nizko koncu odgovor, ampak tudi pomaga priti do hitrosti na turbo hitreje. Na neki točki, ki določen računalnik avtomobile (okoli 3500 RPM) motor odpre dušilna loputa v bypass s polnilnikom in nato de-sklopke polnilnikom za odpravo del izgube. Ta proces omogoča polnilnikom uglašen za nizko koncu odgovor in turbo zvok zakaj višji RPM do priključi na istem motorju. Rezultat je boljša od Volvo ali BMWs 3 konjskih moči in navora krivuljo. 0L pomikanje twin turbos v vseh pogledih, od navora pri nedejavnosti, dolžina navora planote, visokih RPM navorom. Za nadaljnje povečanje učinkovitosti Volvo opira na spremenljivo hitrostjo električni vodna črpalka za hlajenje, neposrednim vbrizgom goriva za učinkovitost zgorevanja in nizko trenje ležajev in obroči. Volvov trženje literature pada to kot odgovor na V8.
Vendar je to res? Ja in št. Pint velika motorja omogoča XC60 raznašati 29 MPG na avtocesti v 304 konjskih T6 trim ki je 50 % povečanje nad Volvov 2009 XC90 V8. Ocena ena za pogon-E. Na cesti, v 2. 0L motor prinaša več nizko koncu navora kot drugi 2. 0L štiri-banger, prodaja v Ameriki razneslo je XC60 več udarec nedejavnosti, kot sem pričakoval. T6′s krivulja navora lahko Laskati kot Volvov razvrščanja, živeli 4. 4 L V8, vendar ne povsem zanesljivo na vrhu ali v prostem teku. Pas širok navora in Aisin 8-stopenjski samodejni dovoljeno XC60 T6 vezati XC90 V8 60 mph. Glasovno naj Volvov burbly V8 je čisti zmagovalec. Različni (vendar izključen) polnilnikom cviljenje pod 3500, dokončno štirivaljni izpušnih Opomba in eerie molka v prostem teku mora motor pogon-E. Volvo je bil Prepreden o vseh Polestar melodije za njihov nov motor, ampak jaz sumničiti, veliko dela bo treba narediti za najboljši Volvov lastnih Polestar I6.
Moj notranji inženir je navdušen možnosti sodobnih kompresorski tehnologij in mala selitev motorjev. Sumim, da bi bilo večini ameriški kupci težko pritisniti, da bi opazili razliko med Volvov twin zaračuna 2. 0L motor in V8 območju 4L sila oddaja in sposobnost vožnje. Stalno pohod proti goriva tudi me navdaja z žalostjo. Ne glede na to, kako ti je rezina, atmosferski V8 je zvok to weve odrasel povezujejo z delovanjem in razkošje. Ta povezava je tako močan, da BMW cevi V8 zveni v kabine svoje turbo V8s, ker je turbos motijo izpušnih opombe. Kot naše pocketbooks veselite, pridružite mi, kot sem shed solza za sesalne inline-6 in V8.

Engine downsizing is all the rage. Making the engine smaller increases fuel efficiency, reduces emissions and cuts vehicle weight. With ever tightening fuel economy legislation in the United States and CO2 emissions regulation in the European Union, mainline manufacturers are turning to turbochargers like never before. In 2009 just 5% of cars sold in America sported turbos, and that 5% consisted largely of European brands like Volvo and BMW with a long history of forced induction. By 2013 that number had more than doubled to 13%. Honeywell expects the number to rise to 25% in the next four years and the EPA tells me that by 2025 they expect 90% of cars sold in America to sport a turbo engine. With turbos becoming so ordinary, whats a turbo pioneer like Volvo do to keep a competitive edge? Add a supercharger of course.
I recently had the opportunity to sample the new Volvo V60 (expect a first drive review shortly) but the star of the show wasnt the car itself, its whats under the hood. New engine designs are truly a rarity in the automotive world with engines being tweaked over time to keep them fresh. Volvos own modular engine found under the hood of most Swedish cars (and the occasional Focus RS) turned 24 years old this year, but its a spring chicken compared to the Rolls Royce L series 6. 75L engine that dates back to 1952. Being the engine nerd I am, I spent a new hours with Volvos powertrain engineer discussing their new Drive E engine family.
Volvos new engine family is primarily a clean sheet design, although many design components are descendants of the old modular engine family. The line consists of four different variants dubbed T3, T4, T5 and T6. As before, T indicates turbocharged but now the number represents power output rather than the number of cylinders involved. Yes, this is the death knell for Volvos funky 5-cylinder because this is a strict four-cylinder lineup. Volvo has said the 149 horsepower T3 and the 188 horsepower T4 wont be headed to America at the moment, so dont expect to see a direct competitor for BMWs downsized 320i from Sweden this year. Instead we get the 241 horsepower T5 and the 302 horsepower T6 under the hood of everything except the XC90.

All engines share a common block design, but what changes is the boost. T3, T4 and T5 engines use a single turbo while T6 adds a Roots-type supercharger in addition to the turbocharger. VW and others have dabbled with twincharging in the past, with VWs 1. 4L twincharged engine finding a home under the hoods of Euro models and putting down 140-180 horsepower. Volvo is taking things to the next step by calling their 2. 0L engine the replacement for not just the 3. 0L twin-scroll turbo but also the recently departed 4. 4L V8.
While supercharging and turbocharging sounds excessive, there is a logic to the madness. While peak torque on the turbo-only T5 just 15 lb-ft lower than the T6 (when in overboost), the supercharger allows the T6 to deliver approximately 140 lb-ft more torque just off idle. The torque curves converge around 1,500-1,600 RPM when the T6 switches over to the turbocharger. From approximately 2,000 RPM to 3,500 RPM torque remains flat on both engines but the larger turbo on the T6 allows it to maintain peak torque all the way past 4,500 RPM. When torque does start to wane it does so more gradually than turbo-only engines.

Why not stick with a supercharger alone like Jaguar and other auto makers? The reason is two-fold. Turbochargers operate off of waste energy from the exhaust. Exhaust gases spin the turbine which in turn spins the compressor forcing more air into the engine. In truth waste energy is a misnomer because there is a horsepower toll for having the turbo interfering with the exhaust stream, but in general this toll is smaller than the power required to operate a supercharger. The downside to a turbo is well known: turbo lag. Turbo lag is the time it takes the turbo to start boosting. Although the turbo is spinning at idle, its creating little positive pressure. Step on the gas and it takes a while for things to start humming along and boost to be created. Thats why the T5 has a lower torque rating off idle.
Superchargers are typically driven off the accessory belt. Because of the direct connection to the engine, they are always creating boost. Because this boost happens in sync with engine RPMs, the response is immediate. On the down side superchargers can consume up to 20% of an engines total power output according to Honeywell. This is considered a good trade since they can boot power up to 50%. Because of design trade offs, factory supercharged engines tend to run out of breath at higher RPMs which explains why Jaguars 5. 0L supercharged engine lags the 4. 4L and 4. 7L twin-turbo German engines by a wide margin in peak torque.
Volvos answer to both problems was to use a supercharger for immediate response at the low end. From idle air flows into the supercharger then through the turbo into the engine. This not only improves low end response but it also helps get the turbo up to speed faster. At some point determined by the cars computer (around 3,500 RPM) the engine opens a butterfly valve to bypass the supercharger and then de-clutches the supercharger to eliminate the inherent loss. This process allows a supercharger tuned for low end response and a turbo tuned for higher RPM running to be joined to the same engine. The result is a horsepower and torque curve superior to Volvo or BMWs 3. 0L twin-scroll turbos in every way, from torque at idle, length of the torque plateau, to high-RPM torque. To further increase efficiency Volvo relies on a variable speed electric water pump for cooling, direct-injection for combustion efficiency and low friction bearings and rings. Volvos marketing literature hails this as the answer to the V8.
But is it really? Yes and no. The pint-sized engine allows the XC60 to deliver 29 MPG on the highway in 304 horsepower T6 trim which is a 50% increase over Volvos 2009 XC90 V8. Score one for Drive-E. Out on the road, the 2. 0L engine delivers more low end torque than any other 2. 0L four-banger sold in America giving the XC60 more punch off idle than I expected. The T6′s torque curve may be flatter than Volvos sort lived 4. 4L V8, but its not quite as robust at the top end or at idle. The broad torque band and the Aisin 8-speed auto allowed the XC60 T6 to tie an XC90 V8 to 60 MPH. Aurally, Volvos burbly V8 is the clear winner. The Drive-E engine has a distinct (but muted) supercharger whine under 3,500, a definite four-cylinder exhaust note and an eerie silence at idle. Volvo was cagey about any Polestar tunes for their new engine, but I suspect considerable work will need to be done to best Volvos own Polestar I6.
My inner engineer is excited by the possibilities of modern forced induction technologies and small displacement engines. I suspect that the vast majority of American shoppers would be hard pressed to notice the difference between Volvos twin-charged 2. 0L engine and a V8 in the 4L range in terms of power delivery and drive-ability. The constant march towards fuel economy also fills me with sadness. No matter how you slice it, a naturally aspirated V8 has a sound that weve grown up associating with performance and luxury. This association is so strong that BMW pipes V8 sounds into the cabins of their turbo V8s because the turbos interfere with the exhaust notes. As our pocketbooks rejoice, join me as I shed a tear for the naturally aspirated inline-6 and V8.