the new actros from mercedes-benz

COVER STORY The New Actros

2 ATZ worldwide 1/2003 Volume 105

DaimlerChrysler presented its new Mercedes-Benz Actros tothe public at the last IAA International Commercial VehiclesMotor Show in Hanover. The new vehicle family, with the 1832to 4158 models, represents the consistent further developmentof the heavy-duty truck launched onto the market in 1996.

By Hartmut Marwitz

and Heiner Harbusch

Der neue Actros

von Mercedes-Benz

You will find the figures mentioned in this article in the German issue of ATZ 1/2003 beginning on page 10.

The New Actros from Mercedes-Benz

3ATZ worldwide 1/2003 Volume 105

1 Introduction

DaimlerChrysler has specifically enhancedthe strengths of these vehicles, which havea 20 % share of the West European market,has met market requirements and drivers'wishes with new, innovative concepts andhas implemented these in the new Actrosfamily. This family encompasses semitrail-er trucks, platform trucks and dump truckswith six cab variants and twelve wheel-base designs. Drive is provided by the tried-and-tested 500 model series V6 and V8 en-gines with increased output.

For the new Actros, development was fo-cused on the segment with the greatest po-tential for growth, for example long-distancehaulage and particularly semitrailer trucksin this case. Thanks to the modular design ofMercedes-Benz trucks and the use of identi-cal components, the relevant innovationsalso benefit the platform trucks and dumptrucks. The aim was therefore to further in-crease the vehicles' overall cost-effectivenessby reducing fuel consumption, reducingweight, reducing servicing and repair costsand extending the service intervals. Safety-relevant features, such as the reduction ofmirror and side window soiling or road illu-mination in vehicle operation during thehours of darkness, were also to be further im-proved. Significant focus was placed on giv-ing consideration to, and implementing, dri-vers' wishes. This is extremely important, es-pecially in long-distance haulage, and great-ly influences the acceptance of a truckamongst other aspects. Of course, the accep-tance and image of a new vehicle also in-volve a modern, appealing and, in the case oftrucks, striking exterior and interior designwhich nevertheless shows that the vehicleforms part of the reliable Actros family. Thenew Actros which is being launched ontothe market is the result of an interdiscipli-nary project work at Mercedes-Benz Trucks,which was characterized by strict processorientation, and consistent project control-ling, innovation and durability.

2 Frame and Chassis

The predecessor's reliable frame concepthas been continued in the new Actros:■ modular frame with 300 mm wheelbasemounting pattern and 50 mm distance be-tween hole centres■ all contours below the top edge of theframe■ uniform frame longitudinal member pro-file height of 270 mm as of the front axlespring bracket■ transverse members designed as U pro-files with different material thicknesses(load-dependent)

■ high-strength E 500 TM material (min.yield strength 500 N/mm2).

Due to the new headlamp concept, thenew entrance and the modified cab suspen-sion, the frame head has been redeveloped.In this context, all of the rivet connectionsused in this area have been switched tothreaded connections. This leads to an opti-mised assembly process in the plant and toa reduction in repair costs. The front under-ride protection is manufactured from high-strength E 700 TM material (min. yieldstrength 700 N/mm2) and is therefore espe-cially effective and also has an optimumweight.

The front cab suspension, which had al-ready been improved in the Actros, was fur-ther developed with the goal of additional-ly enhancing comfort. In order to achievethis, the front friction bearing was replacedwith a rubber block friction bearing and therear molecular bearing with a dual-conebearing in the 1.8 Hz and 1.0 Hz suspen-sions. These bearings have the advantagethat they are less sensitive to material andassembly tolerances, decouple vibrationsbetter and exhibit better wear behaviour. Afurther improvement is the design of thecab’s tilt cylinder as a pivoting lift cylinder,resulting in the prevention of any further

2 Frame and Chassis

Chassis with component-carrier rear end

2-bellows air suspension system



sliding movement in the area of the sus-pension. The tried-and-tested, standard 6Hz cab suspension was integrated into thecorresponding Actros models without anysignificant changes.

The component-carrier rear end is a sig-nificant innovation. The batteries and airvessel otherwise housed in the lateral im-plement carrier on the left side of the frameare located in a vibration-decoupled pan inthe previously unused area between therear axle and end cross member. At thesame time, the other equipment, such asthe four-circuit protection valve, the com-pressed air dryer and the trailer controlvalve, have been uniformly housed in theframe in all semitrailer trucks and variousplatform truck models. The component-car-rier rear end also enables the unimpededuse of standard semitrailers, whereby, ofcourse, adherence to all legally required taillamp visibility and radiation angles is en-sured. The component-carrier rear endleads to the achievement of almost com-plete installation space freedom behind theexhaust system, enabling the customer touse this installation space for diverse at-tachments. Total fuel tank volumes of up to1400 litres (with 3600 mm wheelbase) cantherefore be achieved, for example. Hy-draulic pumps, compressors and other cus-tomer-specific special attachments can alsobe housed. Furthermore, this has also led tothe creation of installation space for attach-ing exhaust gas aftertreatment systems formore stringent, future emission laws, Fig-ure 1. The drive train is shown in.

A constantly accessible jump-startingfacility, by means of which starting assis-tance can be provided with commerciallyavailable terminal clamps, has been in-stalled on the left frame longitudinal mem-ber behind the exhaust system in order torestore mobility in the event of battery fail-ure when a trailer is hitched.

The component-carrier rear end is fittedas standard in all 4x2 semitrailer truckswith Megaspace cabs and air suspensionand all 6x2/2 and 6x2/4 semitrailer truckswith air suspension. The component-carri-er rear end can be ordered as special equip-ment for all other semitrailer truck variantswith air suspension.

The rear axle air suspension in all semi-trailer trucks with partial or full air suspen-sion has also been completely redeveloped.The 4-bellows air suspension used previ-ously has been replaced with a new 2-bel-lows air suspension system, Figure 2. As aresult of this, the standard chassis heighthas also been reduced by 30 mm, therebycomplying with customers’ wishes forgreater body height. Due to the increase inrequirements, the diameter of the new air

spring bellows has been increased (330mm), the bellows pressure has been in-creased from 6.3 bar to 7.6 bar with a per-missible rear axle load of 11.5 t, whilst totalair volume has been reduced from 52 litresto 32 litres. The system pressure of 12 barhas not been changed. Due to the removalof the rear air bellows, the shock absorbershave been relocated to the rear of the axle,leading to advantages in terms of vehicledynamics and roll behaviour. In addition toa weight reduction of over 20 kg, the new 2-bellows air suspension also offers the cus-tomer more favourable repair costs andtimes on replacement of the bellows.

A new variant of the single-stage, hy-poid HL 6 rear axle is also used in the newActros. This axle is a sheet steel axle with apermissible rated load of 13 t, internallyventilated disk brakes and standard differ-ential lock, and covers the output range upto 338 kW. The HL 6 rear axle weighs 90 kgless than the single-stage, hypoid, cast HL 8axle (> 368 kW), which is also still fitted.

Together with the new rear axle and the2-bellows air suspension, the use of super-wide tyres with dimensions of 495/55 R 22.5has also been developed together withBridgestone and BERU. For reasons of safe-ty, the new Actros is then equipped with atyre inflation pressure monitoring system,which provides early warning of pressureloss, and an emergency running elementhoused in the tyre, which enables the dri-ver to handle the vehicle safely in the eventof tyre blow-out. The tyre inflation pressuremonitoring system is comprised of an elec-tronic unit with a pressure and tempera-ture sensor and a high-frequency transmit-ter, which is secured in the rim well. Theelectronic system is driven by a lithiumbattery with a life of approximately 7 years.The driver is able to call up the data in theinstrument in the driver information sys-tem. If the tyre inflation pressure falls be-low the emergency running system activa-tion pressure, the driver is requested to stopby a stop lamp and warning buzzer. Theemergency running element containedwithin the tyre is a hose system which,when compressed, lies on the rim. The tyreand emergency running element are filledwith air by a semiautomatic valve, whichinitially inflates the emergency running el-ement to a pressure of 0.5 bar. At 0.5 bar, aspring opens up additional access to thetyre. The tyre and emergency running ele-ment are then jointly inflated up to the fi-nal pressure.

Following inflation, the inner section ofthe valve is screwed in, thereby sealing theemergency running element. The increasedpressure in the emergency running ele-ment secures this to the rim. On activation

of the emergency running element, causedby negative deviation from a minimum airpressure in the tyre, the emergency run-ning element bursts open and comes to restagainst the tyre as a support. In the event ofa sudden tyre blow-out, the abrupt activa-tion of the emergency running element ad-equately stabilizes the vehicle with suffi-cient rapidity to enable the vehicle to bestopped safely outside any area of danger.With performance comparable to that oftwin tyres, the super-wide tyre above all of-fers the customer a weight advantage of al-most 200 kg (including the omission of aspare wheel).

3 Cab

3.1 ExteriorThe new Actros is most clearly recognizablefrom the newly-designed cab exteriorequipment. The new front-end flap with itsstriking, wide bars and chromed Mercedesstar most clearly characterize the face ofthe new Actros. The rhombic-shaped grillesecured in the front-end flap is availablewith small (V6) and large (V8) rhombic-shaped apertures. The vehicle's new ap-pearance is additionally influenced by thebumper with integrated headlamps. Thebumper has been redesigned as a 3-pieceplastic bumper (steel in construction sitevehicles). The lighting concept has been en-tirely redesigned, with raised headlampunits in order to improve road illuminationand to comply with the legal regulationspertaining to all possible vehicle heightvariants. The new headlamps are of a clearglass look and are manufactured from im-pact-resistant glass, Figure 3. The internalfree-form reflectors house the parkinglamp, dipped beam, main beam and turnsignal lamp. Halogen bulbs are fitted asstandard for the main beam (H1) anddipped beam (H7). The fog lamps (H3) arehoused below the headlamps in thebumper. No further additional headlamps(with the exception of work lamps) are re-quired in the new Actros thanks to the highlight output. Alternatively, vehicles fittedwith air suspension can also be equippedwith xenon bulbs in combination with aheadlamp cleaning system. In comparisonwith halogen, xenon light offers betterspread, greater range and a considerablyhigher life (approximately 2000 h versus600 h).

The newly designed cowling compo-nents at the front of the cab serve to im-prove air flow around the cab, leading, incombination with other measures, to animproved cd value on the one hand and to areduction in side area soiling on the otherhand.



With the exception of the Megaspacecab, the entrance area of all cabs has beenredesigned. Except for the bottom one, all ofthe entrance steps are now secured to thecab and are equipped with corrosion-resis-tant, non-slip, plastic step plates. Individualstep plates can be easily replaced.

The wheel cutouts at the front axle of allcabs are now equipped with a continuous,one-piece fender skirt, thus reducing theegress of dirt from the wheelhouse andthereby reducing lateral soiling.

The generous stowage compartmentslocated in the side wall on both sides of thecab, which can be accessed from outsideand inside, are a significant innovation inthe new Actros, Figure 4. The illuminatedstowage compartments are dimensioned toallow unproblematic storage of all conven-tional beverage crates.

3.2 InteriorPrior to the development of the interior ofthe new Actros, the wishes and require-ments of drivers, passengers and managerswere determined in numerous surveys andworkshops. The result is the interior of thenew Actros, which sets the standard for dri-ver orientation in truck design with its newcockpit, new seats and beds, new, enlargedstowage and storage facilities and its com-pletely new heating and air conditioningsystem.

Developed together with Visteon, thecockpit has a modular design and is avail-able with a short or long centre module de-pending on the equipment and cab. Thecockpit is supported by a tubular steel sup-port, which is securely bolted to the cab andprovides additional torsional rigidity. Thecockpit's appearance is characterized byclear, continuous separating lines. The softsurface, achieved with foam-backed TPOfilms in appealing, modern colours, impartsan impression of very high quality. Severalfunctional storage facilities, cup holdersand ashtrays are integrated into the instru-ment panel. A spacious drawer is locatedbeneath the centre module. Depending onequipment, the driver is provided with upto 3 sockets (24 V and 12 V) for connectingelectrical equipment.

The new instrument, developed togeth-er with Siemens VDO, with optimised dis-plays and an integrated driver informationand control system, is located centrally inthe driver's field of vision, Figure 5. The in-strument is deeply recessed into the instru-ment panel. Together with a curved lens,this leads to outstanding, dazzle-free legi-bility. Several variants of the instrumentare installed, starting from a low-line vari-ant (construction site vehicles) to a high-line variant (long-haul vehicles) with a

3.2 Interior

Cockpit

Ergonomically favourable position of shift lever

Single cab equipment


variable, green area which shows the driverthe engine speed range currently mostfavourable to consumption. Part of the newinstrument is the trip computer – similar tothat in a passenger car – which can be usedto call up current, important vehicle andconsumption data.

The consistent driver orientation em-ployed in the new Actros is also revealed invehicle function operation. As has alreadybeen successfully implemented in passen-ger cars, the new Actros is equipped with amultifunction steering wheel with fourcontrol buttons which can be used to actu-ate the telephone, radio with CD or CC andthe FIS driver information system menu,but also the emergency running functionfor the Telligent® automatic transmission.Within the cockpits, the functions are con-trolled via individual switches, which havebeen comprised to form functionally-relat-ed groups, for example chassis, air condi-tioning, cab, telematics, Figure 6. In vehi-cles with little equipment, the remainingswitches are always relocated to offer thedriver optimum accessibility. This is madepossible by a CAN bus-capable switch gen-eration, enabling each signal switch to beinserted almost anywhere in the switch

panel. This leads to a very compact switchlayout without the use of otherwise neces-sary dummy covers. The space acquired asa result of this can be used for additional,small storage compartments. In the newActros, the parking brake valve is now lo-cated in the instrument support for easy ac-cess. It can therefore be reached immedi-ately even in the event of an emergency.The window lift, mirror adjustment andheated mirror controls have been relocatedfrom the storage facility on the engine tun-nel to the door module in line with thefunctions. As always, the main beam, turnsignal lamps, horn, windshield wipers,window cleaning system, cruise controland permanent brake are actuated via thetwo steering column switches on the leftand right. The sensor unit for the new, fur-ther-developed Telligent gearshift (3rd gen-eration EPS) is located in an ergonomicallyfavourable position on a seat-mounted con-sole, Figure 7, which can be folded up to-gether with the gearshift in order to facili-tate passage through the cab.

The ventilation, heating and air condi-tioning systems significantly contribute to-wards comfort and cosiness in the cab. Anair conditioning system regulated on the

air side, in which the temperature is con-trolled by mixing cold and hot air via ablending air flap, is employed for the firsttime in the truck market in the new Actros.Corresponding air ducting at the wind-shield and specific, punctiform air emissionlead to fogging-free windows and verypleasant, stratified-temperature air distrib-ution in the cab.

In the case of the auxiliary air heater, thehot air is no longer emitted into the cab viaa nozzle located behind the driver's seat,but is blown into the heater system airducts, leading to more rapid and even dis-tribution in the cab. The heater system isavailable in three designs, with manualtemperature control, as a manually con-trolled air conditioning system and as anautomatic air conditioning system with anair quality sensor AQS.

In the new Actros, the driver's and pas-senger's seats are specifically tailored to thedifferent vehicle operation profiles, Figure8 and Figure 9. The familiar standard andluxury suspension seats with new seat cov-ers can be found on the driver's side. On thepassenger side, these are supplementedwith a completely redesigned functionalseat, whose seat cushion can be folded up


3.2 Interior

Ergonomically formed seats

Highquality beds


(cinema seat) to improve usage of the spaceinside the cab. A reclining seat, upholsteredin velour with an especially wide seat cush-ion and backrest, is also available as a fur-ther new feature. This seat has an integrat-ed reading lamp and can be set to an espe-cially relaxing position thanks to its wideadjustment range. One further option fordesigning the passenger's seat is offered byselecting single-cab equipment as a singledriver package. Instead of the passenger'sseat, a wide, comfortable seat with widearmrests is integrated into the lower bed inthis case. This seat is also equipped with athree-point seat belt, allowing it to be usedas a standard seat for transporting a secondperson.

The new Actros is equipped with high-quality beds instead of the previous bunkswith foam mattresses, Figure 10. The lower“standard bed” (710 mm wide x 1950 mmlong) is equipped with a spring-cushionedmattress. The rear wall, which has beenpushed out by 110 mm in the area of thelower bed, helps to improve spatial com-fort. The upper luxury bed (800 mm wide x2020 mm long) is equipped with a sprungwooden grating to support the spine; thiscan be individually adjusted to suit the userby inserting pads (spring plates) with dif-ferent degrees of hardness. The upper bed,the passenger's reclining seat and the luxu-ry suspension seat have been awarded theAGR quality seal (Aktion Gesunder Rücken[Healthy Back Campaign] registered associ-ation).

By specifically redesigning the stowagecompartments in the area of the rear wall,the stowage space, a contributing factor fora positive assessment of suitability forlong-distance haulage, has been almostdoubled. The storage boxes and drawers onthe rear wall of the cab are modular and areavailable in different combinations de-pending on the cab variant. They are char-acterized by considerably improved acces-sibility and different functions, for exampledesigned as a drawer or alternatively as arefrigerator.

Further practical storage facilities withvarying volumes are located in the sidewalls, in the doors and in the area of theraised roof above the doors. Depending onthe height of the roof, two different storagesolutions are available above the wind-shield; the long-distance haulage variantwith raised roof is the most striking ofthese. The radio, tachograph and CB radioare located in the lower, three-section stor-age facility above the driver, whilst a lock-able valuables compartment (13 litres) canbe housed in the right section. The levelabove this houses three large, illuminatedand lockable stowage boxes.

The cab is illuminated by high-perfor-mance, dimmable interior lighting withseparately controllable work area illumina-tion and a spotlight for reading. Greennight lighting, which is easy on the eyes, isavailable as orientation lighting. The interi-or lighting can be controlled using switchesin the storage facility above the wind-shield, from the passenger's door controlpanel or from the bed via the switch panelon the rear wall.

4 KontAct Electronic Concept

The electronic unit in the new Actros, de-veloped under the internal Daimler-Chrysler title “KontAct” is a further signifi-cant innovation. This is a decentralizedelectronic concept which has been extend-ed with various bus systems, Figure 11.

The functions are laid out decentrally inthe basic module (with integrated servicesystem, anti-theft alarm system and com-munications processor in the cab) and thefront and rear module (with integratedride height and roll control in the vehicleframe). The basic module also acts as acommunications interface to the interiorCAN bus and the frame CAN bus. The ad-vantages of such a concept involve a re-duction in the number of connectors andleads and a reduction in the lead cross-sec-tions between the individual modules. Dif-ferentiation from the competition isachieved by innovative combinations ofsensors and actuators and simple exten-sion with additional electronic systems.This networking enables the implementa-tion of a multifunction steering wheel, im-proved on-board computer operation andthe extended interior lighting strategy. Themultiple usage of individual signals in thevehicle can also be achieved effectively inthis way.

5 Engine

The new Actros is equipped with the tried-and-tested model series 500 engines in fur-ther-developed form, Figure 12 and Table.All engines have undergone a moderate in-crease in output (exception: V6 335 kW) incomparison with the predecessor. The en-gine torques have been increased by up to 8 %. All of the engines comply with theEuro 3, Stage 1 emission standard.

In order to further improve quality, theengines have been subjected to a series ofadditional measures, such as the use of ahigher-strength material and reinforce-ments on the cylinder head, an optimisedcylinder head gasket, modified injectorsand the use of new pistons with an im-proved cooling effect.

Measures for reducing gas exchangelosses have been implemented in order tooptimise fuel consumption. A new fan withbetter aerodynamic efficiency and an elec-tromagnetic fan clutch, and a new tur-bocharger with increased air throughputand optimised efficiency, have now beeninstalled.

New intake valves and seat rings manu-factured from more durable materials havebeen fitted in order to extend the service in-tervals. The oil separator has beenequipped with a cyclonic insert and, as ofautumn 2003, service intervals will be ex-tended (150,000 km) via the use of a bypassoil centrifuge in combination with a high-er-volume plastic oil pan (V6 engines). ■

Model kW Nm

OM 501 LA 235 1.650265 1.850300 2.000*320 2.100*335 2.200

OM 502 LA 370 2.400*395 2.500425 2.700

*4 eco-points

Table: New engines

5 Engine

the new actros from mercedes-benz

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