2005 Jeep Liberty Jeep Goes Diesel: The Diminutive Liberty Takes a Big Step

Towards Raising SUV Fuel Economy Text and photography by Rob Reaser

Seeking to replace their aging Cherokee mid-size SUV while providing a more compact, stylish model to entice the growing ranks of urban sport utility vehicle buyers, Jeep released its all-new Liberty for the 2002 model year. Now, a scant three model years later, the popular Liberty has been treated to several updates not the least of which is the first use of a diesel engine in a mid-size SUV. Diesel engines are gaining a more prominent position in the minds of the consuming public, as everyone looks to improve fuel efficiency and reduced operating costs. For Jeep, the timing for the introduction of its high-tech Common Rail Diesel (CRD) could not be better.

In America, traditionally, diesel engines have meant chuggy powerplants best suited for over-the-road semi and fleet trucks rather than urban daily drivers. Yes, certain European import sedans and wagons have found a small market here, but loathe as we are to follow any lead from the continent across the pond, traditional small Diesels have never enjoyed the popularity here that they do in Europe. Now, however, in the case of the new generation common rail diesel engines, the wine-and-cheese contingent may indeed show us a better way. The CRD engine found in the Jeep Liberty Diesel is one of those powerplants that pleases just about anyone looking into the mid-size SUV market. Although its 2.8L displacement may seem wimpy at first blush, its numbers quickly dispel such notions. Horsepower is a smart 160 at 3,800 rpm comparable in performance to most V6 engines in this class. Torque output is where the CRD truly shines brightest. Coming in at a whopping 295 lb/ft at 1,800 rpm, this number places the Liberty Diesel in the same ring as V8s which power full-size pickups. Consider the CRDs stablemate, the Dodge 4.7L Magnum SOHC. That powerplant has a solid 1.9L displacement advantage over the CRD, yet its torque rating is the same at 295 lb/ft. However, it doesnt hit that peak until 3,600 rpm. For its size, the Liberty Diesel is a powder keg of muscle and it does most of its grunt work way down in its rpm range, right where you want it.

You cant see much of the 2.8L CRD I4 due to the noise-dampening cover, but when in operation theres no

mistaking the peculiar tinkle of a VM Motori of Cento, Italy diesel engine at work.

To pick back up on the European connection, many of you may know the Europeans have been ahead of the curve in advancing diesel technology in the passenger car market. Most of the best diesel engines (Cummins notwithstanding) are rolling off that continents assembly lines. Such is the case for the CRD found in the refreshed Liberty. Its built by VM Motori of Cento, Italy a company owned since 1995 by Detroit Diesel, a DaimlerChrysler company, which we all know is in the hands of the Germans. (The increasingly incestuous nature of this industry continues to amaze...)

http://www.vmmotori.it/en/index.jsphttp://www.vmmotori.it/en/index.jsp

Youre not going to stuff a whole lot of gear in the back of the Liberty with the rear seats in the up position, but

the cargo capacity is good enough for most grocery hauls (note the grocery bag hooks incorporated in the seatbacks).

Anyway, VM Motori has been a leading diesel technology manufacturer for over half a century, and has supplied engines for the Jeep Cherokee in Europe since 1994.The CRD powerplant went into production in 2001. So, in reality, this is nothing new to Jeep from a global perspective. Its just new to the North American Jeep marketplace. The CRDs hook, if you will, is its common rail direct injection fuel system. To better understand how it works, lets run through a quick primer on the mechanics of diesel engines.

For 2005 the rear seats fold flatter to make for a more level cargo floor. In this configuration, cargo capacity

goes from 29 to 69 cubic feet.

As you know, gasoline engines (electronic ignition) utilize a combination of air, fuel and electrical spark to provide combustion. On its downstroke, a piston simultaneously draws air and atomized fuel into its combustion chamber. On the pistons upstroke this mixture is compressed and ignited by the spark plug to provide the power stroke. Diesel engines, by contrast, do not use an electric spark for ignition. Instead, the piston draws only air into the cylinder, which is squeezed on the compression stroke to the point where the air is extremely hot. At some point in the compression stroke, atomized fuel is delivered into the system. When the fuel hits the hot, compressed air, the mixture ignites and the power stroke is initiated. This is why diesels are also referred to as compression ignition engines.

The window switches are relocated on the center console for 2005 for a more ergonomic placement.

This may sound a bit crude to those schooled in the EFI arts. In reality, however, current diesel engines have a whole lot going for them. For example, they excel in fuel efficiency, in part because they allow for high compression ratios (compare Jeeps 2.8L CRD compression of 17.5:1 to its sibling 2.4L EFI engine with 9.5:1 compression). Higher compression ratios usually mean better fuel efficiency in terms of power output and consumption. Additionally, diesel fuel contains more energy per unit than does conventional automotive-grade gasoline. Its also less (should be) expensive because it does not require as much refinement as pump gas.

Back seat passengers dont fare too poorly in the Liberty. Forward-opening doors, mildly bolstered seats,

integral headrests and 37.2 inches of legroom make rear occupancy tolerable.

Diesel engines have been around for a while (since 1892, to be exact), and to American minds theyve always been viewed as loud, clunky, dirty and low on vicarious performance. So whats the excitement about now? It all has to do with ever-improving technology and the incorporation of the common rail direct injection system. Traditionally, diesel engines used what is called indirect injection, where a pre-chamber in the cylinder head mixes air and fuel, and begins the combustion process before the full fuel charge is sent into the combustion chamber. This was necessary in order to optimize the air/fuel mixture prior to it entering the combustion chamber. The result was a loss of some fuel efficiencies, noise, heat loss and relatively high particulate emissions, to name a few of its detractions.

Enter the common-rail direct injection system, such as is found on the new Jeep Liberty Diesel. The CRD relies on high pressure fuel delivery (rated to 23,000 psi) to send highly atomized fuel directly into the combustion chamber. All of the cylinder injectors are linked to a single, or common, high-pressure fuel rail (hence the name) that is fed by a cam-driven high-pressure pump. The whole operation is run by an electronic control system that is quite similar in operation to conventional EFI systems. Performance is computer-controlled to deliver the optimal fuel pressure, injection duration and injection timing to achieve an acceptable balance of power output and fuel economy. Compared to the indirect injection pre-chamber system, noise is down, fuel consumption is down, power output is up, and emissions quality is significantly improved. The 2.8L Liberty engine actually uses two pilot injections, which come on before the main injection, to further reduce the edgy nature of diesels and smooth idle noise. Furthermore, the Liberty incorporates an electronically controlled turbocharger. This unit uses moveable vanes to optimize power output and fuel efficiency across the power band.

The next best thing to drop-top off-road adventure is a sunroof, and for $700 you can have one in the Liberty.

So, thats what all the hype is about. The question is, how does it feel? Prior to field testing, we had picked up on some Internet chatter about how the Liberty Diesel was noisy. What a bunch of brie-and-cognac whiners! Yeah, the CRD is no purring kitten, but then...ITS A DIESEL! One things for sure...its the quietest diesel in a domestic 4x4 weve ever tested. Actually, its not bad at all. By tweaking the timing and fuel delivery events, placing the engine on hydro mounts, adding damping material here and there, stuffing a resonator into the air induction tract, and dropping a massive engine cover over the four-cylinder, the CRD doesnt sound loud to us, just neat...like its got some real character going on. Get over it, already. On the road the Liberty Diesel isnt going to win you any streetlight jousting tournaments, but on the other hand it has a pretty fancy snap for a four-cylinder once the turbo kicks in. Acceleration, however, isnt this 4x4s bag rather, its torque. And torque it has. The max trailer weight is 5,000 pounds. We can almost see a Liberty Diesel hauling butt to the coast with a 20-foot runabout in tow, causing gawking passersby to remark something like...What?

Theres certainly nothing fancy about the Libertys interior dcor, but for most off-highway adventurers, that is as it should be functional, without being overbearing. New seats and fresh fabric choices are part of the 2005

changes.

The 2.8L turbo diesel option is not available on the Liberty Renegade, only the Sport and Limited models, and it comes only with a five-speed automatic transmission. ABS is also part of the diesel package.

After only three model years since its introduction, the Liberty receives some minor body updating for 2005. The Sport model seen here benefits from higher fog lamp and park/turn lamp placement, a new front fascia,

new body-color grille with fog lamp provisions, and new rocker panel protection.

Do we like the Liberty Diesel? You bet. In fact, given its 22/27 city/highway fuel economy, pleasing diesel hum, and stump-ripping, rock-rolling torque, our money goes here. After all, while the Renegade and Limiteds 3.7L V6 may have it in the horsepower department, lets face it, the Liberty is no corner-carving SUV. It does a fine job under moderate road driving, but its real deal is its dual on-/off-road credentials. If high-end horsepower and slot car handling is what you crave, get a Corvette Z06. If, instead, you want a maneuverable trail rig thats got the beef where it counts, the Liberty Diesel is waiting for your test drive. What Else Is New? The CRD engine is not the only new balloon floating at the Jeep Liberty party this year. Inside and out the Liberty gets a bit of a facelift. Changes include:

Renegade - flatter hood, body color grille, new rocker panel protection, molded-in color front fascia with a Bright Silver Metallic appliqu, standard tow hooks, body-color bolted flares with chrome-plated attachment details, new luggage side rack with Brushed Silver Metallic tubular side rails, black off-road light bar is now optional.

Limited - chrome grille, chrome bodyside molding (with Liberty name molded in), chrome side rails, new rocker panel protection.

Sport - body-color grille, higher fog lamp and park/turn lamp positions, front fascia, rocker panel protection.

Interior - relocated power window switches, instrument cluster graphics (white letters on gray background), new seats with dual-density foam, new seat fabrics, reduced rear seat fold angle.

Functional - new NSG370 six-speed manual transmission replaces the five-speed manual (Sport and Renegade availability).

Ultima generazione

2.8 Lpassa i limiti...has no limits...

T he R 428 DOHC 05MY is theevolution of VMs current 2.8L4 cylinder engine. This newversion features a number of signi-ficant improvements.In order to respect the ever morestringent emission limits andmarket demands for high perfor-mance engines, the R 428 DOHCuses the most advanced technolo-gical solutions.The use of Common Rail injectionat 1600 bar, variable geometryturbo, highly efficient emissioncontrol devices and counter-rota-ting balance shafts guaranteeimpressive performance and fuelconsumption while at the sametime reducing noise and vibrations.

The engines 120 kW power ratingand torque of 400 Nm (more than80% of which is available at 1400rpm) make for outstanding perfor-mance and greater flexibility andresponsiveness even on vehiclessuch as Minivans and SUVs.VM Motori is very aware of environ-mental issues, and has put its longexperience in this field into practiceon this new engine. The result is anengine that meets the current USstandards (US Tier 2), which heavilylimit NOx and particulate emissions.Specific attention has been alsodedicated to noise and vibrations.Double pilot injection, counter-rota-ting balance shafts and intake throt-tle valve improve driving comfort.

Fast metallic glow plugs, controlledby an Electronic Control Unit, assureimmediate engine start-up andimproved combustion not only in thefirst few seconds of the engine run-ning but also whenever the ambienttemperature falls below 0C.The R 428 DOHC 05MY will be afurther important step towardspublic appreciation of diesel engi-nes, and will strengthen VMs posi-tion in the prestigious car sector.

Il motore R 428 DOHC 05MY e le-voluzione del noto motore VM a 4cilindri 2.8L che, gi presente sulmercato, si presenta per lanno 2005con significativi miglioramenti.Per rispettare le normative emissio-ni sempre pi stringenti e le richie-ste prestazionali del mercato, ilmotore e stato dotato delle piavanzate soluzioni tecnologiche.Il sistema di iniezione Common Raila 1600 bar, il turbo a geometriavariabile, dispositivi emissioni adalta efficienza, e masse controro-tanti consentono di raggiungereragguardevoli livelli di prestazioni,consumi, riducendo, al contempo,rumorosit e vibrazioni.La potenza di 120 kW e in particola-

re la coppia di 400 Nm (di cui pidell80% disponibile a 1400 giri) per-mettono prestazioni brillanti e gran-de elasticit di marcia anche su vei-coli della categoria Minivan e SUV.Sempre sensibile ai problemi del-lambiente, VM ha concentrato suquesto motore la sua lunga espe-rienza nel controllo delle emissioninocive. Il risultato un motorecapace di rispettare le severe emis-sioni americane (US Tier 2) che, invigore dal 2004, limitano fortementeil rilascio di NOx e particolato.Particolare attenzione stata dedi-cata anche alla rumorosit e allariduzione delle vibrazioni. La doppiainiezione pilota, le masse controro-tanti e la valvola di spegnimento

migliorano il confort di guida.Le candelette veloci controllate dauna centralina elettronica consen-tono di avviare il motore senza atte-sa, di migliorare la combustione neiprimi secondi di avvio e, in genera-le, in tutte le situazioni con tempe-rature ambientali al di sotto dellozero.Il motore R 428 DOHC 05-MY se-gner un altro passo in avanti nelfavore del pubblico per le motoriz-zazioni a gasolio e rafforzer laposizione di VM nel settore dei vei-coli prestigiosi.

Turbo VGT Incremento prestazioni del 10% 80% della coppia massima dispo-

nibile a 1400 g/min. Incremento efficienza sistema EGR

VGT Turbocharger Performance increased by 10% 85% of maximum torque available

at 1400 rpm EGR system efficiency improve-

ment

Common Rail Gen. II Pressione di iniezione: 1600 bar Doppia iniezione pilota Riduzione dei consumi, rumorosit

ed emissioni

Common Rail Gen. II 1600 bar injection pressure Double pilot injection Redution of fuel consumption,

NVH and emission.

Centralina elettronica Controllo motore completamente

elettronico Adattamento dei parametri iniezio-

ne alle condizioni di guida eambientali

Autocontrollo dei valori di emis-sione

Electronic Control Unit Full electronic control Injection parameter control depen-

ding on driving and environmentalconditions

On board diagnostic for emissions

Candelette veloci Accensione motore immediata

anche a basse temperature Miglioramento della combustione

a freddo

Fast glow plugs Immediate engine start-up, even at

low ambient temperature. Improved combustion at low

ambient temperature

Tipo di moto

Cilindri - Co

Alesaggio e

Rapporto Co

Interasse cil

Cilindrata un

Cilindrata to

Caratte

ore - Engine Type

onfiguration 4 In-linea - In-line 4

Corsa - Bore & Stroke (mm) 94 x 100

orsa/Alesaggio - Stroke/Bore Ratio: 1.06

lindri - Bore Pitch (mm) 112

nitaria - Unitary Displacement (cc) 692

otale - Total Displacement (cc) 2766

Diesel ad iniezione diretta4 stroke Diesel Direct Injection Rapporto di Compressione - Com

Potenza massima - Max Power

Coppia massima - Max Torque

Sistema di iniezione - Injection Sy

Sistema di aspirazione - Air Induc

Emissioni - Emissions

eristiche tecniche

...e sbarca in America

mpression ratio 17.5:1

(kW/rpm) 120 @ 3800

(Nm/rpm) 400 @ 1800

System

ction

US Tier 2 (Euro IV capable)

Common Rail Generazione IICommon Rail II Generation

[rpm]

[Nm] [kW]

200

250

300

350

400

450

500

550

600

650

1000 2000 3000 40000

15

30

45

60

75

90

105

120

135

PowerPower

TorqueTorque

PrestazioniPerformancesTechnical features

...and embarks in America

Sovralimentato VGT/IntercoolerTurbocharger VGT/Intercooler

54

682

DimensionDimension

Valvola EGR elettrica Alta velocit di risposta

Maggiore precisione Riduzione delle emissioni nocive

Electric EGR valve Rapid response High precision

Reduction of exhaust emissions

Alberi di equilibratura Riduzione delle vibrazioni agli alti

regimi

Balance shafts NVH reduction at high speed

EGR Cooler Scambiatore di calore ad alta

efficienza per ridurre leemissioni di NOx

EGR Cooler High efficiency heat exchanger for

reduced NOx emissions

Valvola a farfalla Incremento ricircolo gas di scarico

Riduzione delle vibrazioni in fasedi spegnimento

Intake throttle valve Increased recirculation of gaseous

emissions Reduced engine shake during

shut down.

0

682

nins

is registered trademark of VM MOTORI. As technical advancements continue, specification may change. Printed in Italy - VM MOTORI Advertising Department - Cod. 4 250 6017 F - M2 - 11.04

44042 CENTO (Ferrara) - Italy - Via Ferrarese, 29Industrial - Marine: Tel. +39 - 051- 6837 511 - Fax +39 - 051- 6837 517e-mail: automotive@vmmotori.comwww.vmmotori.it

ISO 14001 - Cert. n 0043A/0

Azienda di progettazione, produzione e commercializzazione di motoridiesel con Sistema Qualit ed Ambiente certificato.

Company with the Quality and Environmental system certified for dieselengine design manufacturing and commercialization.

ISO 9001 - Cert. n 0295/2ISO/TS 16949 - Cert. n 2920/0

VM MOTORI preferisce/prefers