Mercedes-Benz Citaro with all-electric drive system technology

Mercedes-Benz Citaro with all-electric drive system technology

Mercedes-Benz has promoted the all-electric Mercedes-Benz Citaro as taking electric mobility using city buses to a new level altogether.

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The 12-metre variant will celebrate its world premiere in September at the IAA Commercial Vehicles, with the start of series production coming before the end of the year. The new Citaro offers an impressive and hitherto unknown standard of energy efficiency, courtesy of its innovative thermal management system.

The intelligent modular concept for its battery and charging technology is a similarly compelling proposition. The electric Citaro is also more than simply a city bus: Mercedes-Benz takes a holistic view of electric mobility, embedding the Citaro firmly within its overall eMobility system.

This comprises services that range from individual and very practically oriented advice ahead of any purchase and recommendations relating to charging infrastructure through to taking on servicing work at the customer's own workshop.

Citaro: from low-emission bus to zero-emission bus

Back in 2012, this became the first city bus in the world to meet what is currently the most stringent emissions standard, Euro VI.

The Citaro hybrid variant then became a fully recognised low-emission bus. Launched last autumn, it features a hybrid module that further optimises the performance of the combustion engine and reduces the already low fuel consumption by as much as 8.5%. Compared with a city bus meeting the Euro V standard, the CO2 emissions have thus fallen by almost 20% and the nitrogen oxide emissions by as much as 98% in just a few years, while particulate emissions have even reached the limits of detection.

The Citaro hybrid, featuring innovative 48-volt technology, dispenses with the need for a high-voltage network and is available as an option for the majority of Citaro variants, including for the natural gas-powered Citaro NGT. This model is particularly quiet-running and its emissions low, while when fuelled by biogas it is virtually CO2-neutral.

Proven electric axle, new modular battery concept

The drive system of the new all-electric Citaro is based on the tried and tested ZF AVE 130 electric portal axle with electric motors at the wheel hubs, as previously deployed in other variants of the Citaro. Their peak output of the motors is 2 x 125 kW, while torque is 2 x 485 Nm.

Lithium-ion batteries with a total capacity of up to about 243 kWh are responsible for providing the power. These are modular in design: the batteries are split between up to ten modules, each supplying around 25 kWh. As well as two battery modules on the roof, the standard equipment includes four battery modules in the rear of the bus.

Each battery module is made up of 15 cell modules, together with a control unit for monitoring purposes and as a means of balancing the charge of the battery cells. Each separate cell module houses twelve battery cells. Mercedes-Benz uses easily manageable prismatic cells with a capacity of 37 Ah each.

With a minimum of six and up to a maximum of ten battery modules possible, transport operators can adapt their usage and charging strategy very precisely to individual needs. Opting for the largest number maximises the range of the buses, while a smaller number reduces the weight as well as the cost of purchase and allows more space for passengers – but potentially makes time-consuming interim, or 'opportunity', charging necessary.

With the maximum complement of ten battery modules, the all-electric Citaro with standard equipment weighs around 13.7 tonnes. In conjunction with a permissible gross vehicle weight of 19.5 tonnes, this corresponds to a payload of 5.8 tonnes or around 80 passengers – even in the rush hour, as is commonly necessary.

The Citaro's engineering has been future-proofed. Since the development of battery technology is progressing at a rapid pace, provision has already been made for the transition to the next generation.

Dana to supply all-wheel drive axle for new Volkswagen Crafter panel van

Dana to supply all-wheel drive axle for new Volkswagen Crafter panel van

Dana Incorporated is supplying its Spicer AdvanTEK M180 all-wheel-drive axle to the new, award-winning Volkswagen Crafter 4 Motion panel van.

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The axle – manufactured at Dana's Birmingham, England, facility – is said to provide exceptional reliability, durability, comfort, and efficiency in a compact design to meet stringent performance requirements throughout the Crafter's anticipated long service life and high-mileage city driving.

"Dana's advanced driveline solutions such as the Spicer AdvanTEK series and SmartConnect disconnecting all-wheel-drive technology have built upon Dana's history of being a technology leader in Europe and around the world," said James Kamsickas, Dana president and CEO. "Leveraging our foundation of world-class engineers and more than 10,000 patents over our history, Dana has dramatically increased customer satisfaction through class-leading technologies and operational excellence. These focused efforts have significantly contributed to dramatic revenue growth and an increase of pre-tax earnings of 46% over the past three years."

A key feature of the axle is its advanced electronic-locking differential. As part of the complete system design, the robust four-pinion rear-locking differential incorporates an electric solenoid with an electronic position sensor to lock the wheels together for improved traction and stability. Dana was responsible for ensuring the locking differential application software met Volkswagen's demanding functional safety requirements. For added convenience, drivers can turn the system on and off with the touch of a button when improved traction is desired.

"Our team worked closely with Volkswagen from start to finish to develop and launch the best solution for the all-new Crafter 4 Motion. We are proud to be part of this vehicle, the 2017 International Van of the Year," said Christophe Dominiak, senior vice president and chief technology officer of Dana. "The new axle on the Volkswagen Crafter is a great example of Dana's leadership in efficient all-wheel-drive integration technologies and our ability to partner with our customers to provide them the solution they need to meet ever-changing market demands."

The company also launched its Spicer AdvanTEK M250 rear axle – also manufactured in Birmingham, England – for rear-wheel-drive versions of the VW Crafter. This axle is designed to handle heavier payloads while providing optimal traction and power density, even when the vehicle is fully loaded.

Dana launches Spicer S172 Series single drive axle for Class 7, 8 trucks

Dana launches Spicer S172 Series single drive axle for Class 7, 8 trucks

Dana introduced its new Spicer S172 series single drive axle for Class 7 and 8 vehicles during a press conference at the Technology & Maintenance Council annual meeting in Atlanta.

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According to Dana, the new axles retains the robustness and strength of the existing S170 drive axle while reducing weight by more than 60 pounds.

The axle is crafted for 4×2, 6×2, and 8×2 applications up to 25,000 pounds gross axle weight rating. It offers a broad range of gear ratios, from 3.07 to 6.14, and features a low hypoid offset with High-Power Density AdvanTek gearing to optimise efficiency. The high-strength pinion bearings allow for greater lifespan under heavy loads, improving durability and overall performance, the company said. In addition, a passive lube management system has been added that requires less lubricant overall while maintain optimum lobe flow.

"It uses a venturi-cover design to optimize the lube flow in the axle and to make better use of the available lubricant, so we require less lubricant that a standard axle," said Steve Slesinski, director of Dana's global product planning. "We coupled the venturi-cover with a patented lube meter that controls the amount of lubricant going in between the bearing system of the pinion. That helps reduce spin losses due to churning and thus improves axle efficiency."

The single drive axle can also be paired with the Dana tag axle as part of the Spicer EconoTrek tandem axle, a durable, lightweight 6×2 configuration that offers increased fuel economy, improved performance, and reduced maintenance for heavy-duty linehaul tractors. This system is up to 3% more efficient and up to 380 pounds lighter than typical 6×4 offerings.

The tandem version is more than 60 pounds lighter than existing D170 series tandem axles, and it's available in a broad range of gear ratios, from 3.07 to 6.14, to serve a variety of needs, especially heavy-haul applications such as the Canadian logging sector with GWV up to 160,000 pounds and 50,000-pound gross axle weight ratings.

"Dana engineers are continuously examining innovative ways to improve our existing products," said Mark Wallace, president of Dana Commercial Driveline Technologies. "We were able to build upon the advanced features of the S170 and make it lighter without sacrificing its industry-proven durability and efficiency. We remain a company committed to finding a better way to address the needs of our customers and the commercial-vehicle market."

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