With more than 12,000 units sold since its launch in 1997, the Mercedes-Benz Citaro low-floor bus is the European market leader in its segment. It can be seen on routes in almost all of Europe’s major cities, from Oslo and London to Rome and Istanbul. Its success is founded on sophisticated, economical technology as well as innovative design and a wide-ranging line-up. The Citaro is available in urban bus or rural-service bus guise as well as with a choice of different body lengths. Now the new Mercedes-Benz Citaro LE extends the range even further. Available as an urban regular-service bus or a rural-service bus with a choice of two body lengths, it opens up the growing „Low Entry“ segment for the Mercedes-Benz Bus and Coach unit.
Low Entry: passenger-friendly and economical
As the term „Low Entry“ suggests, these buses feature a low-floor design from the front section up to and including the centre entrance, with a raised floor behind the centre entrance (door 2). As well as providing a high level of passenger comfort, even for passengers with restricted mobility, this „composite“ design also allows the uncomplicated, economical and therefore cost-effective and maintenance-friendly installation of the major assemblies. Low Entry regular-service buses also have an extremely neatly arranged passenger compartment with a relatively high number of twin seats in the rear section, where all of the seats face towards the front of the vehicle. Demand for the Low Entry design has been particularly high in Scandinavia and the Benelux countries to date. Now, thanks to the new and highly attractive concept at the heart of the new Mercedes-Benz Citaro LE, demand is set to rise not just in these countries but also in Central Europe.
Citaro LE based on an ingenious concept
During the development phase of the Citaro LE, the main aims were to ensure maximum economy for the operators and an extremely passenger-friendly design. So, rather than being a stand-alone product, the new Citaro LE is directly descended from the sophisticated, tried-and-tested Citaro low-floor bus. Since both buses are based on the same modular system, they share numerous components such as the doors, electrical/electronic system, destination displays, seats, interior panelling and air conditioning. The same goes for the body skeleton, which is based on the tried-and-tested „modular system“ structures and components used for the raised-floor rural-service buses and also includes a specially raised rear module for the new Citaro LE. This intelligent design allows a high level of variance and opens up a whole range of customisation possibilities – a benefit with which operators of
Citaro low-floor buses will be familiar.
Tried-and-tested components from low-floor and raised-floor buses
The Citaro LE combines the advantages of a low-floor bus with those of a raised-floor bus. Both regular-service buses – the Citaro LE and the Citaro – are practically identical up to the area behind the centre entrance door. The powertrain at the rear is also a well proven, highly economical, series-production item – the engine, drive axle, transmission and substructure frame are lifted from the Integro rural-service bus and the Travego RH high-deck touring coach.
At the front, the low-floor area of the Citaro LE is exactly the same as that in the other Citaro buses, making the Citaro LE eligible for subsidies. In the rear section of the passenger compartment especially, passengers benefit from enhanced ride comfort thanks to the use of rural-service bus and touring coach components. And the raised roof allows standing room at the rear of the Citaro LE as well as at the front. However, the Citaro LE has only been raised where necessary. Since the bus features the same front body section as the standard Citaro, the feeling of spaciousness is as pleasant and harmonious at the front as it is at the rear. At the same time, however, the vehicle manages to maintain its sleek exterior lines – the Citaro LE is perfectly proportioned and shows no signs of bulkiness. So it blends in exceptionally well when out on the road.
The Citaro LE is available in rural-service bus or urban regular-service bus guise. Based on an efficient and well thought-out concept, the new Low Entry bus delivers outstanding economy and provides a whole host of individualisation options.
Citaro LE has a distinctive look
In terms of exterior appearance, too, the Citaro LE is a class apart. On the one hand it is unmistakably a Citaro, on the other it has an aura all of its own. One of the most prominent features of the side design is the rear section of the roof, which has been raised by 310 mm and blends in harmoniously with the vehicle body. Extended side elements on the roof create an elegant link between the front and rear sections. By using the familiar front section of the Citaro and not increasing the height in this area, the designers have created a well-proportioned overall look. The optionally available roof-mounted air-conditioning system can be fitted in its famil-iar place, as on the Citaro. Appearance-wise, passengers will scarcely notice the difference between the Citaro and the Citaro LE at the front end.
The raised roof at the rear is made from fibreglass-reinforced plastic and is gently stepped to the side, making the bus appear higher. Since the advanced „modular system“ principle is at work here, the roof edge profile is the same as that of the
Citaro at the rear. A slightly curved and blackened mesh-type surface in the side window area creates a smooth transition between the windows of the front and rear sections, so there is no hint of an abrupt join. Keen observers will notice the new frameless, hinged windows and the grey instead of green tinted glass used for all the windows except for the driver’s window and the front entrance door.
A rear end with the design vocabulary of a touring coach
At the rear, the lines of the raised roof sweep elegantly down into the new-look rear panel. The rear end is now more three-dimensional in shape and features elegant radii. The V-shaped rear window is drawn impressively upwards, stretching as far as the roof. At its uppermost limit, the engine flap is rounded off by a ventilation open-ing covered by a black mesh plate. On the whole, the design vocabulary is reminis-cent of the new Mercedes-Benz Travego touring coach. Such family similarities are unmistakable and quite intentional. The close ties with the touring coach are also highlighted by the three-dimensionally prominent tail lights with a single glass cover. Originating from the same modular system as the tail lights on the new Travego, the Citaro LE tail lights, tapered in design, are drawn deeply around into the vehicle flanks. There is also a new-look bumper. Together, these measures give the new regular-service bus a more coherent, less angular form.
Front end design with a face that fits
There are major differences between the new Citaro LE and the familiar first-generation Citaro regular-service bus at the front end, too. Although the two wind-screens for the urban bus and rural-service bus, including the destination displays, remain the same - as do the main headlamps - the indicator housings have been turned upwards at the outside to give the bus a friendlier appearance. Like the headlamps, the indicators have clear-glass covers. Furthermore, a continuous black moulding appears to draw the windscreen further downwards and makes the wiper arm attachments seem as if they are set further back.
Last but not least, the Citaro LE now has a „face“. As in the case of the low-floor
Citaro, new features include a curved recess which gives the impression of a radiator grille between the headlamps, creating a further visual link with the grille of the new Travego. This is where the Mercedes star now stands proud on its own special base. Slightly smaller in diameter than the star on the Citaro, it has been modified in line with the stars on the other Mercedes-Benz buses and coaches. The position of the badge with the emblem and star directly above this has been moved upwards into the dark film area to make it easier for companies to apply their own lettering and livery.
Where as the front-end flap on the current Citaro low-floor bus seems to have been added on, the Citaro LE has a flush-mounted flap and the bumper has a softer shape. The tapered fog lamps integrated in the bumper are the same as those at the front of the Travego touring coach. None of the screwing points are visible at the front end of the Citaro LE. Like the front-end flap, the corner panels, including the headlamp housings, can be opened, making the entire front end ideally accessible for maintenance work. The same is true of the front box with the heating and ventilation system for the driver, which has been moved to the left and is now accessible from the side by means of an outside flap, in contrast to the Citaro’s front box.
Like the rear-end design, the new face of the Citaro LE emphasises the family resemblance with other buses and coaches displaying the Mercedes star, serving notice of a new, shared design direction. Based on the tried-and-tested and extremely sophisticated Citaro, these changes mark the introduction of a new, clearly more emotive and typically Mercedes design vocabulary for regular-service buses, which is much more touring coach-oriented than before. The other members of the Citaro family are also set to benefit from this new design direction.
The Citaro LE has a distinctive look. At the front and centre entrances, the new
Low Entry regular-service bus benefits from its close family ties with the Citaro: the front and centre entrances are only 320 mm and 340 mm above the ground respectively. If an optional third door behind the rear axle is ordered, the first step, which is also only 340 mm high, is followed by three flat steps, each 200 mm high, lead-ing to the centre aisle.
New-look ceiling with smooth transition between the bus sections
The close associations with the Citaro are also clearly evident in the passenger area of the Citaro LE, which includes wall-mounted cantilever seats for the urban bus as well as twin seats with aisle-side steel feet and the classic handrails which curve outwards at the top. However, the design vocabulary of the Citaro LE has been further refined and adapted in line with the special requirements that have to be met by a Low Entry bus. So whilst the inclined ceiling side panels are taken from the
Citaro, they merge into the main part of the ceiling practically seamlessly in the
Citaro LE. The new ceiling – smooth, easy to clean and trimmed in aluminium – features specially adapted strip lighting. Another harmonious feature of the ceiling design is the smooth, curved transition between the low-floor front section and the raised rear section. This highly successful design feature is impressively rounded off by the brand lettering displayed prominently in the bulkhead area.
The rural-service version of the Citaro LE has all-new rural-service bus seating. All the passenger seats from the front end to the area above the rear axle have spacious, trough-shaped luggage racks overhead. The rack base is perforated to allow passengers to keep an eye on their luggage from below. In addition, grab rails are mounted on the luggage racks for the benefit of standing passengers. Options available for the rural-service version include integral service units comprising venti-lation nozzles, reading lights and buttons for the passenger stop request system.
Two flat steps leading to the rear section of the vehicle
In front of the rear axle, two flat steps, each 200 mm high, lead to the raised-floor area at the rear. Thanks to the roof, which has been raised by 310 mm, the feeling of spaciousness at the rear is as pleasant as at the front of the bus. Here the floor rises by no more than 7 degrees, and the standing room is at least 1.90 metres. The higher floor and the platforms, which are no higher than 200 mm, allow an extremely homogeneous seat arrangement at the rear of the bus. All of the seats face forwards and rise steadily from front to rear like cinema seats.
Refined driver’s area and windscreen with thermal insulation glass
The Citaro LE has largely the same driver’s workplace as the Citaro, including the tried-and-tested VDV instrument panel, for example. To the left of the driver’s area are new, generously proportioned compartments which can be supplemented by an optional electrically cooled bottle compartment. Further features on the left-hand side, mounted on a console, include switches for additional functions and the parking brake lever.
The Opticool windscreen, already used in the touring coach models, is a new addition and offers extremely effective thermal insulation. It absorbs infrared rays and lets through around 10 % less heat and energy, thus considerably reducing the interior temperature and enhancing the driver’s comfort and wellbeing. The interior design of the front section has also been enhanced on a visual level. Boarding passengers are now met by the Mercedes-Benz brand lettering at the entrance. And a closed cover in the semicircle of the instrument panelling conceals the fire extin-guisher in the Citaro LE, in contrast to the visible fire extinguisher in the Citaro. The width of the centre aisle between the front axle wheel arches is a wheelchair-friendly 920 mm.
Independent front suspension
Several parts of the Citaro LE chassis have been modified, marking a significant departure from the Citaro chassis. Here again, economy and passenger-friendly design are key factors. Further new equipment includes independent front suspension, which makes the Citaro LE unique as no other series-production urban bus in Europe can currently boast this comfort-enhancing feature.
The design is based on lower wishbones and a front axle with a standard-fit stabiliser which, incidentally, can also be installed as an option on the rear axle. Benefits of the new independent suspension system include extremely impressive straight-line stability, less road impact on the steering, lower unsprung masses and a
general improvement in handling and ride comfort, since the wheels do not affect each other if the road conditions are worse on one side of the vehicle than they are on the other. Even though the entrance height is identical, the Citaro LE has a greater ground clearance - 165 mm - beneath the front axle, thus reducing the risk of bottoming. The steering gear has been moved further rearwards and is now out-side of the area at risk in the event of an accident.
Small turning circle and excellent ride comfort
In addition, the front axle has a very large steering angle (inside: 53 degrees, out-side: 46 degrees), making the bus extremely manoeuvrable. The 12 metre long
Citaro LE has the same turning circle as the highly agile Citaro – just 21.5 metres – despite its long wheelbase length of 6,035 mm (as against the Citaro’s 5,845 mm).
Furthermore, the driver and passengers benefit from enhanced ride comfort as, compared to the Citaro, the maximum spring travel has been increased by more than a third from 70 mm to 94 mm, the air spring volume per bellows has been boosted by over 10 % to 10.5 dm³ and the natural frequency has been reduced substantially. The result is, by low-floor bus standards, extremely sure, smooth and comfort-oriented handling.
HO6 rear axle for coach-like ride comfort
Due to the raised floor concept at the rear, the bus is fitted with the HO6 hypoid axle, a tried-and-tested performer in the Mercedes-Benz Integro, Tourismo and Travego models for a number of years. The main advantage of the hypoid axle over the portal axle fitted on buses with a low floor throughout is the single-stage ratio of the centrally positioned differential, meaning low inner frictional resistance and, as a result, the favourable fuel consumption figures. What’s more, the noise level is also noticeably lower.
Since there is more installation space available for the rear axle below the raised floor area of the Citaro LE, an extremely effective suspension system offering coach-like ride comfort can be fitted. The maximum spring travel of the HO6 axle is 70 % or 50 mm higher than that of a portal axle – 120 mm as opposed to 70 mm – whilst the air volume of each of the four air bellows has been increased by more than 20 % from 9.0 dm³ to 11.11 dm³. The rear axle has two longitudinal links and an upper and lower wishbone in the middle.
Powerful engines with outputs ranging from 210 kW (286 hp)
to 260 kW (354 hp)
The Citaro LE powertrain incorporates standard components from the Citaro as well as from the Integro rural-service bus and the previous Travego RH. Like these vehicles, but in contrast to the Citaro, the Citaro LE has its engine mounted centrally at the rear for easy servicing. The base engine is the tried-and-tested OM 457 hLA six-cylinder in-line powerplant with a displacement of twelve litres. This turbodiesel engine is able to fulfil the most stringent of performance requirements when heavily laden and operating in areas with demanding topography. Installed horizontally in the Citaro LE, it is available with an output of 220 kW (299 hp) or 260 kW (354 hp), with a peak torque of 1,250 Nm and 1,600 Nm respectively.
In addition, from the middle of 2007 onwards, the vertically installed OM 926 LA six-cylinder in-line engine with a displacement of 7.2 litres (210 kW/286 hp) and a maximum torque of 1,100 Nm – already installed in the Mercedes-Benz Axor heavy-duty truck – will be fitted in the Citaro LE, marking the powerplant’s debut in the bus segment.
BlueTec reduces nitrogen oxides and particulate matter
without increasing fuel consumption
All of the Citaro LE engines, with the exception of a limited quantity of Euro 3
models produced during the initial phase, comply with the Euro 4 emissions
standard and are based on the new BlueTec technology that has proven such a success in Mercedes-Benz Actros heavy-duty trucks since the beginning of the year. Based on SCR (Selective Catalytic Reduction) technology, BlueTec enables ni-trogen oxide emissions to be reduced by up to 30 % (if a current Euro 4 engine is fitted) or 60 % (if a future Euro 5 engine is fitted). A positive side effect, thanks to exhaust gas aftertreatment which optimises the combustion process, is an 80 % re-duction in particulate emissions compared to Euro 3 – a strong argument given the current debate about soot and exhaust-gas emissions. Last but not least, fuel con-sumption is lower than in the previous Euro 3 engines – another attractive benefit in times of persistently high fuel prices.
In terms of fuel tank capacity, the Citaro LE urban bus can carry around 280 litres of diesel whilst its rural-service counterparts can hold around 350 litres. As for
AdBlue, the Citaro LE urban bus has a capacity of around 38 litres whilst the figure for the rural-service versions is around 46 litres, which is generally sufficient for two full tanks of diesel. In the case of the Citaro LE, the AdBlue filler neck is located be-hind an additional flap right next to the filler hole for the diesel tank. The mineral oil industry is currently putting in place a comprehensive AdBlue supply network.
AdBlue manufacturers can also supply the fluid in different pack sizes suitable for companies that operate their own filling stations or pumps.
Choice of manual or automatic transmission
As in the case of the Citaro low-floor bus, the automatic transmissions for the
Citaro LE are sourced from either ZF or Voith. There is also a brand-new option available for the Citaro LE rural-service bus in the shape of the GO 190 six-speed manual transmission in conjunction with the EPS 3 automated gearshift system. All of the transmissions send the drive power to the HO6 hypoid axle, which is already successfully fitted on the Integro, Tourismo and Travego models. To ensure that the optimal configuration is achieved for the application profile in question, a total of eight different transmission ratios are available, covering the entire regular-service bus spectrum. Theoretically the maximum speed ranges from 82 km/h to 114 km/h, but it is limited to 100 km/h.
Engines positioned to ensure easy servicing
Thanks to the raised-floor design at the rear of the Citaro LE, all of the powertrain components are easily accessible and therefore extremely easy to maintain. This applies to the engine and the transmission as well as to the air cleaner, which is lo-cated in the engine compartment itself. Further examples of easily accessible com-ponents in the Citaro LE include the battery compartment, which can be found right next to the centre door in the platform on the right-hand side. Not to mention the compressed air reservoirs for the brake system and the auxiliary heater, which are situated in easy-to-reach positions on the opposite side.
Variants of the new Citaro LE
The Citaro LE range comprises two-axle urban and rural regular-service buses. The Citaro LE urban bus is 12 metres long and comes with a choice of two or three doors. Both of the rural-service bus versions – the Citaro LE Ü (12 metres long) and the Citaro LE MÜ (13.1 metres long) – have two entrance doors. They also have the option of a two-leaf entrance door at the front, which the urban bus version includes as standard. All variants of the Citaro LE are 2.55 metres wide and have a maximum height of 3.3 metres at the rear. Depending on the seating arrangement and door variant, the Citaro LE urban regular-service bus can carry between 85 and 91 passengers. Meanwhile the rural-service version has capacity for between 65 and 80 passengers (plus the driver’s seat in each case), depending on the vehicle length, the seating arrangement and doors.
Production of the Citaro LE begins in autumn 2005, starting with the 12 metres long urban regular-service bus. In spring 2006, production will be extended to in-clude rural-service buses with a length of either 12 metres or 13.1 metres. All of the models are to be produced at the Mannheim plant. Both 12-metre variants of the Citaro LE will be celebrating their premiere at this October’s „Busworld 2005“ show in Kortrijk, Belgium. The Citaro LE Ü rural-service bus will be on display in the hall and the Citaro LE urban bus can be viewed in the adjoining open-air area.