Promote and demand
The Rhein-Ruhr transport association (VRR), of which WSW mobil GmbH is also a member, launched a promotional programme for buses with hybrid technology in 2009. Today approximately 70 hybrid buses belonging to VRR transport companies have been subsidised with the help of the programme for "Innovative projects for the improvement of local public transport". The objective is to pool the findings and experience gained with regard to the new technology as part of a research programme and put them at the disposal of other transport companies and vehicle manufacturers. Ulrich Piotrowski is responsible for the market launch of hybrid and electric buses at Mercedes‑Benz. He believes that: "Wuppertal is just perfect for using the Citaro G BlueTec Hybrid. The demanding topography provides sufficient opportunity for energy recuperation via the brakes, but, if necessary, can also clearly demonstrate deficits thanks to the challenging routes. The experience gained during daily operations is invaluable to the further development of vehicles."
Mercedes-Benz Citaro G BlueTec Hybrid
When topographical conditions are ideal, the Citaro G BlueTec Hybrid can drive up to 10 kilometres using exclusively electric power without the help of the diesel engine. Four electric wheel hub motors which draw their power from lithium ion batteries provide the drive. Electric current is generated when the brakes are applied and, if required, can also be obtained via a generator which is driven by a small diesel engine. Experts speak of a serial hybrid in this context.
Needs-based equipment
The technically sophisticated diesel-electric hybrid concept has been realised in the well-established articulated version of the successful Mercedes-Benz Citaro urban bus family. The light blue vehicle hardly differs from the rest of the WSW Citaro fleet. The bright and friendly interior is characterised by large windows. The traffic red grab rails are a contrast to the blue seat covers. A video surveillance system with five cameras improves safety and avoids damage through vandalism. The climate control in the passenger compartment and at the driver's workplace can be regulated independently of one another via the overhead air-conditioning system. The air-conditioning concept, just like the fire alarm system and the automatic fire extinguishing system in the engine compartment, is standard WSW equipment.
Two 48.26 cm TFT monitors in the front and rear sections display the names of bus stops. When connected to the IBIS on-board computer, information regarding route progress and the name of the next bus stop are displayed. The IBIS is not only responsible for the control of the passenger information systems, but also for traffic signal preemption in Wuppertal. The control centre can directly transmit acoustic and visual information to one or all of the vehicles on the service route. The exact position of the vehicle is determined, evaluated and transmitted to the passenger information boards located at the bus stops using GPS. Passengers at the bus stops are thus informed in real time about exact arrival and departure times.
HighTec in urban buses
Four electric motors influence the driving characteristics of the Citaro. They accelerate the 18 meter long bus quickly and almost silently. As no transmission is used, passengers notice no jerking typical of gear changes. The drive output of the wheel hub motors is 320 kW, supplied as required by the battery and the diesel engine driven generator. These electric motors are also used for braking the vehicle. They then function like generators and convert the brake energy into electric current for the battery. If the battery indicates that it requires more power, the diesel engine automatically starts in order to generate additional energy. In comparison to a bus that runs on diesel only, the combustion engine is only half the size, weighs only 450 kg instead of 1000 kg and its engine capacity is 4.8 litres as opposed to 12 litres. At 160 kW, its output is about one third lower.
The energy storage unit used in the Mercedes‑Benz Citaro G BlueTec Hybrid is a lithium ion battery. The battery system supplies a maximum of 240 kW and, weighing less than 350 kg, is comparably light. Compared to conventional battery systems, batteries with ion technology impress with a higher energy density in conjunction with a greater storage capacity and lower weight.
WSW mobil GmbH
At present the 100 percent subsidiary of the Wuppertal Stadtwerke GmbH employs around 740 employees. In 2010, 89.6 million passengers used the WSW mobil GmbH services. The bus fleet comprises approximately 300 regular service buses. Together the 65 service routes are 633.7 km long, whereby the service stretches from Wuppertal and Solingen via Remscheid to as far away as parts of the Ennepe-Ruhr district.
Credits: Daimler AG
Copyright © 2012, Mercedes-Benz-Blog. All rights reserved.
B 180 BlueEFFICIENCY produces 16 percent less CO2 emissions than its predecessor
The neutral inspectors at the TÜV Süd technical inspection authority have confirmed the high environmental compatibility of the new Mercedes B-Class, awarding the compact sports tourer the Environmental Certificate in accordance with ISO standard TR 14062. This certification is based on a comprehensive ecological life cycle assessment of the B-Class, documenting every detail of ecological relevance.
"The new B-Class is the first model of a completely new generation of compact vehicles from Mercedes-Benz. It sets clear benchmarks in two fields which are crucial to efficiency – aerodynamics and the drive system," explains Professor Dr Herbert Kohler, Chief Environmental Officer at Daimler AG. "The high level of environmental compatibility goes beyond reductions in fuel consumption, as the Environmental Certificate in accordance with ISO standard TR 14062 now confirms."
Mercedes-Benz analyses the environmental compatibility of its models throughout their entire life cycle – from production through their long years of service to recycling at the end of their lives. This analysis goes far beyond the legal requirements. The Environmental Certificate and supplementary information are made available to the public in the "Life Cycle" documentation series, which can be found at http://www.mercedes-benz.com .
Over the entire life cycle of the Mercedes-Benz B-Class – from production and service over 160,000 kilometres to recycling – the new model in the guise of the B 180 BlueEFFICIENCY with 7G-DCT dual clutch transmission causes 16 percent less CO2 emissions than its predecessor when the latter was discontinued in 2011. The energy balance shows a similarly positive picture, with primary energy consumption over the vehicle's entire life cycle cut by 14 percent in comparison to its predecessor. This corresponds to the energy content of around 2400 litres of petrol.
The marked reductions in fuel consumption represent a substantial contributory factor here. By way of example, the fuel consumption of the B 180 BlueEFFICIENCY petrol model with dual clutch transmission ranges – depending on the fitted tyres – from 5.9 to 6.2 l/100 km in comparison to 7.3 to 7.5 l/100 km for its predecessor (at the time of its discontinuation in 2011). This corresponds to a substantial reduction in fuel consumption of up to 19 percent. These fuel savings are ensured by an intelligent package of measures – the so-called BlueEFFICIENCY technologies. These include optimisation measures in the area of the powertrain, energy management, aerodynamics, tyres optimised for minimum rolling resistance, weight reduction through lightweight construction and driver information to encourage an energy-saving style of driving. An outstanding drag coefficient of Cd = 0.26 places the new B-Class at the forefront of its market segment.
The B-Class already meets the recycling rate of 95 percent by weight which will be mandatory as of 1 January 2015. In all, the B-Class incorporates 75 components representing a total weight of 39 kilograms which can be produced with the partial use of high-quality recycled plastics. This results in a 13 percent increase in the weight of approved recycled components in comparison to the previous model. Typical areas of use are wheel arch linings, cable ducts and underbody panels, which consist for the most part of polypropylene.
There is also an increased emphasis on closed automobile materials cycles: a recyclate is used for the front wheel arch linings, for example, which is produced from reprocessed vehicle components such as starter battery housings, bumper panels from the Mercedes-Benz Recycling System (MeRSy) and production waste from cockpit units.
21 components in the B-Class, representing a total weight of 20 kilograms, are produced using natural materials – an increase of 29 percent over the previous model. Natural materials employed in series production of the new B-Class consist primarily of coconut and wood fibres and honeycomb cardboard in combination with various polymer materials.
The modular body-in-white concept means that the B-Class is designed to accommodate versions with an alternative drive: appropriate interfaces in the body shell enable the main floor panel to be modified and a step to be produced for the "ENERGY SPACE" on the versions with alternative drive. An underfloor compartment covering part of the area under the rear bench seat offers space for alternative energy accumulators.
Credits: Daimler AG
Copyright © 2012, Mercedes-Benz-Blog. All rights reserved.
To coincide perfectly with its market launch on 19 November 2011, the new M-Class has received a very special award: the premium SUV has become the first vehicle in its class to obtain the much sought-after environmental certificate in accordance with ISO standard TR 14062. With this approval, the independent examiners of the German TÜV Süd are honouring the commitment which the corporation is making to comprehensive environmental protection, an aspect which is firmly embedded in the operating guidelines for the entire Daimler Group. As part of these processes, the automotive manufacturer takes into account the effect which a vehicle has on the environment throughout its entire life cycle – from development via the production process and operation right through to disposal. The environmental certificate is therefore based on an exhaustive Life Cycle Assessment (LCA) for the M-Class.
Based on the ISO standard TR 14062, the certificate is valid for all models of the
M-Class. Using the Mercedes-Benz ML 250 BlueTEC 4MATIC by way of example, factors such as energy requirements and emissions over a distance of 250,000 kilometres were calculated. As a result of this, the SUV took the leading position in its market segment as a champion of efficiency: it consumes only 6.0 litres of diesel per 100 kilometres (158 g CO2/km) and, thanks to innovative SCR (Selective Catalytic Reduction) exhaust gas technology with AdBlue injection, already undercuts the EU6 guidelines planned to be introduced in 2014.
Compared with the previous model, the ML 300 CDI BlueEFFICIENCY 4MATIC from 2011, over its entire life cycle the new M-Class achieves 25 percent (18 tons) less CO2 emissions, 38 percent less nitrogen oxide emissions and, thanks to the lower fuel consumption and the use of SCR technology, primary energy savings of 24 percent. Compared with the previous model at the time of market launch in 2005, namely the ML 280 CDI 4MATIC, the savings are even greater: in this case it has been possible to reduce CO2 emissions by 32 percent (25 tons), nitrogen oxide emissions by 62 percent, and primary energy by 31 percent. The primary energy savings of 31 percent equate to the energy content of around 9800 litres of diesel fuel.
In addition to the ML 250 BlueTEC 4MATIC, impressively high efficiency results were also achieved by the ML 350 BlueTEC 4MATIC, as well as the petrol model, the ML 350 4MATIC BlueEFFICIENCY: compared with the previous models, the entire model range consumes an average of 25 percent less fuel.
The outstanding fuel economy figures achieved by the efficiency champion come courtesy of new development tools, including the "energy-transparent vehicle", for example. Developed by Daimler and used exclusively in the automotive industry, this process enables development engineers to examine the entire flow of energy throughout the vehicle (tank to wheel). The knowledge gained in this way can be used to optimise every single assembly that has an impact on fuel consumption, right down to individual components, such as wheel bearings.
Stable loop: recycling and natural materials in the M-Class
No less than 37 high-quality recyclate components have been approved for use in the M-Class. These include wheel arch linings, cable ducts, and under body panels. Wherever possible, recyclate materials are derived from vehicle-related waste streams. The aforementioned front wheel arches are made from recovered vehicle components, for example starter battery casing, bumper covers or process waste from cockpit production. Overall, the weight of these recycling parts has increased by 29 percent compared with the predecessor. This concept also contributes to the M-Class already being able to comply with the recycling rate of 95 percent which is due to be introduced throughout Europe from 2015.Renewable materials are used in 15 components in the M-Class. The total weight of components manufactured using renewable materials is 13.1 kilograms, a figure which has increased by 153 percent compared with the previous model. Renewable materials are mainly used in the interior of the M-Class, but there are also some technical applications: olive coke is used for the activated charcoal filter, which adsorbs hydrocarbon emissions from the tank and is constantly regenerated during driving operation.
The environmental certificate and a detailed description of what it entails have been made available to the general public in the form of the "Life Cycle" documentation series, which can be found online at www.daimler.com and www.mercedes-benz.com .
Source: Daimler AG
Copyright © 2011, Mercedes-Benz-Blog. All rights reserved.
