Citaro hybrid is coming

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Daimler has unveiled a commercially viable, mild hybrid version of the Mercedes-Benz Citaro that will be available in right-hand drive in the UK from mid-2018. That and the new Tourismo RHD coach, launched in June, are just two of the product innovations coming to the British Isles that will be highlighted at Busworld Europe, Kortrijk next month as Andy Izatt explains

Daimler announced last year that the Citaro ‘E-Cell’ electric will go into series production in 2018. Head of Development at Daimler Buses, Gustav Tuschen told CBW at the manufacturer’s pre Busworld Europe, Kortrijk press briefing in Stuttgart last week that it remains on schedule and the hope is that a right-hand drive version would be available in 2019. The fully electric bus would be able to cover 90-95% of bus routes although also offering a fuel cell range extender is under consideration.

The Citaro hybrid delivers a fuel saving of up to 8.5% compared to a Euro 6 diesel equivalent. ANDY IZATT

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The German multinational anticipates that by 2025 half the buses it builds will be electric – generally now seen as the preferred solution for public transport in urban centres. However, a key new product will be publically unveiled at Busworld next month that is designed to meet the broader requirement for a ‘green’ solution where electric traction won’t be appropriate or practical.

What is being launched is a commercially viable diesel or CNG (Compressed Natural Gas) mild hybrid Citaro where it will be possible to amortise the anticipated additional cost over four years. Against the backdrop of an increasingly prescriptive political climate, Daimler believes it has found a practical way of extending diesel engine acceptability while at the same time maximising its efficiency and that of its CNG equivalent. The design modifications it has had to make have been minimal.

As well as utilising an electrohydraulic intelligent ‘Eco Steering’ system for the first time, what is a parallel hybrid system has a drive that incorporates proven components already used in the Daimler truck and passenger car ranges which has helped to minimise the add-on cost. What’s delivered is a fuel saving (and consequential emission reduction notably in CO2) of up to 8.5% compared to a Euro 6 diesel Citaro. Compared to a Euro 5, that’s a 20% improvement and the 8.5% is also additional to the 15% reduction delivered by the Euro 6 Citaro NGT (Natural Gas Technology) over its Euro 5 predecessor.

An electric motor already deployed in the Mercedes-Benz S-Class car generates a maximum output of 14kW and 220Nm of peak torque to assist the combustion engine when high levels of power are required such as when the bus moves off. A slight boost effect from the motor at idling speed also increases engine efficiency with power being recouped through braking and during coasting.

Euro 6 Citaro variants already utilise smaller supercaps to store electricity generated while coasting, but larger ones in two roof-mounted modules with a 2Ah total capacity are specified in the hybrid. These supercaps have a 10-year life and are better suited than batteries to the continuous quick changeover between charging and discharging that occurs during bus operation. Braking to a stop just once from 50km/h will recharge them.

There is no elaborate high-voltage network with Daimler’s hybrid, the manufacturer opting to use a separate 48-volt system similar to that found in its hybrid passenger cars. That and the electric motor are not the only components taken from existing product ranges. The additional radiator for the electric motor and invertor is used in Mercedes-Benz trucks and the water pump in cars.

Compact technology and a straightforward design mean the hybrid drive adds just 156kg to the vehicle’s unladen weight so the impact on passenger capacity is minimal. In a rigid bus with a GVW (Gross Vehicle Weight) of 18 tonnes, 105 passengers can be carried.

The drive, installed between the combustion engine and gearbox, is available across the entire Citaro range with the exception of OM470 engine options because of the lack of space available and in the high-passenger capacity CapaCity for the same reason. By coincidence the 50,000th Citaro happens to be a CapaCity for Wiener Linien, Vienna and it was one of the vehicles displayed at the Stuttgart press briefing.

At 60,000km or once a year, maintenance intervals are the same for the Citaro hybrid as its diesel equivalent. The 48-volt system is classified as low-voltage technology so there’s no requirement for extensive training courses, special tools or dedicated replacement parts. All auxiliary assembles remain unchanged and are driven conventionally.

As an interesting aside, Daimler has no plans to offer a start-stop engine function because of the “burden” it creates. “It does not lend itself to city bus operation,” said Gustav.

Hartmut Schick, Head of Daimler Buses, said: “For 20 years the successful Citaro has been the dominant urban regular-service bus in Europe and far beyond. The clean, efficient and safe Citaro city bus is our answer to the traffic problems in towns and cities. The new Citaro hybrid demonstrates that we are continuously further developing the Citaro.”

For UK coach operators the new Tourismo RHD is clearly the most important of Daimler’s latest product offerings. ANDY IZATT

Enhanced coach

For UK coach operators the new Tourismo RHD is clearly the most important of Daimler’s latest product offerings and the first orders have already been taken. While there were tri-axle top and two-axle bottom of the range examples on display in Stuttgart, reflecting what will be exhibited at Kortrijk, the first right-hand drive 51-seater which was at the Brussels launch is now with EvoBus UK and will show debut at Coach and Bus UK at Birmingham’s NEC on October 4-5.

CBW comprehensively reported on the Tourismo RHD following its June launch (CBW, June 27, 2017). While it perpetuates the well respected and established Tourismo name, it is an entirely new model available in four lengths between 12.295 and 13.935m carrying up to 60 passengers and with two different inline six-cylinder engine options.

As well as lower overall TCO (Total Cost of Ownership), fuel savings in the region of 4.5% are promised and Daimler says if operators factor in the consumption advantages of its latest efficiency package for the OM470 engine, that increase can be as much as 7% – between 1,500 and 2,000-litres of fuel based on an annual mileage of 100,000km. Taking into account all enhancements and capital costs, it says customers could see their monthly costs reduced by a double-digit figure compared to its predecessor.

New to Tourismo RHD since its launch is the optional inclusion of Active Brake Assist 4 (ABA 4) from Quarter Two, 2018 which warns the driver visually and audibly of a potential collision with pedestrians while at the same time automatically initiating partial braking.

An electronically scanning multi-mode radar is used comprising long and short-range systems. The long-range one registers multi-track vehicles and stationary obstacles at a maximum distance of 250m in a direct line in front of the coach, single-track vehicles such as bicycles at up to 160m and pedestrians at 80m. The short-range radar with a maximum range of 70m can detect pedestrians and vehicles to the side ahead. ABA 4 is available free of charge to customers that select adaptive cruise control as that provides the necessary radar technology.

Setras on display at Busworld will include the TopClass S515HDH, ComfortClass S511HD and MultiClass S415LE business, but making its show debut will be the new TopClass S531DT 14m-long double-decker with 78 Voyage Ambassador passenger seats covered in Gecko pebble moquette and with dark evogrey headrests in UK-manufactured E-Leather.

Daimler’s minibus exhibit is an interesting one from a British Isles perspective as it’s a left-hand drive City 45, a 22-passenger capacity, 7.36m-version of the Sprinter range that was previously only available in right-hand drive.

Hartmut Schick, Head of Daimler Buses: ‘For 20 years the successful Citaro has been the dominant urban regular-service bus in Europe and far beyond.’ ANDY IZATT

Omniplus On

Daimler will continue to enhance the support it provides customers with the introduction of Omniplus On, which comes to the British Isles at the same time it’s rolled out across the rest of Europe. Omniplus On will integrate all digital services so operators will have personalised access to everything they have subscribed to through one portal.

Omniplus On will integrate the numerous telematics services of Fleetboard, whether it’s operating analysis (looking over the driver’s shoulder), tour recording, mapping, driver time management or evaluating key operating data such as warning messages and alerts. From the beginning of 2018 ‘Fleetboard Bus Data Centre’ telematics boxes that serve as the transfer unit for the host data will be fitted as standard to all Citaros and Tourismos. The new electrics/electronics platform B2E, a technical requirement for the use of Omniplus On, will be available from Quarter three.

Omniplus Uptime is a further development of Omniplus 24h Service with telediagnostics, which permanently monitors the status of vehicle systems in real time. That includes all the technical features equipped with sensors that provide information to the CAN data bus system – around 30 components and functions including engine management and exhaust after treatment.

If the need for repairs or maintenance is apparent, a message is automatically sent to the operator, and depending on urgency, also to the authorised service outlet. If a problem occurs that could lead to a breakdown, the operator will additionally receive a phone call from Omniplus 24h Service within minutes of it being identified. Omniplus Uptime will even reveal inattentiveness such as a failure to perform a particulate filter regeneration when it should have happened or continuing to leave a tyre pressure at an inadequate level.

A basic free service already provides operators with a great deal of information such as the fuel saving potential of the fleet using current fuel consumption figures and driving styles, the mileage of vehicles and their current location. It’s also already possible to access servicing guidelines and operating instructions amongst other information.

However, Remote Bus monitor’s vehicle functions such as tyre pressures, diesel and AdBlue levels, whether luggage compartment flaps are locked and the status of all exterior lights on touring coaches, and from Spring 2018, drivers will be able to access all that information via the WLAN (Wireless Local Area Network) using a smartphone.

Omniplus On’s relevance to the driver is further underlined by an app that provides a list covering everything he or she is supposed to check when taking a vehicle over. Any shortcomings can be recorded in writing and by photo and sent to the operator with the check-up report. Further items can be added to the checklist and the app can also be used to send additional or revised information to the driver such as details of an itinerary change.

The range of digital services available under the Omniplus On brand is set to be continuously expanded.[/wlm_ismember]