MAN Lion’s City Hybrid – the innovative city bus that brings greater ecological balance and economy to urban mobility
- Successful market launch in cities and pilot regions all over Europe. Moderate growth expected for 2012.
- The serial hybrid drive is optimal for heavy urban traffic. Fuel savings of up to 30 percent in practice.
- The way to E-mobility: diesel-hybrid is today's optimal combination of affordable technology and achievable CO2 reduction.
After its market launch, the MAN Lion's City Hybrid is already operating in regular service in 15 European cities. Here, the bus with its serial hybrid system has confirmed that it is considerably more efficient in heavy urban traffic than the most modern conventional diesel-powered city bus. Its savings in fuel consumption of up to thirty percent are convincing - this is equivalent to reducing CO2 emissions by the same percentage. In practical operation, the bus is just as reliable and safe: regular service sees these buses on the road for 20 hours out of every 24.
After intensive research and gruelling field tests, the MAN Lion's City Hybrid was launched onto the market as a series-production vehicle in 2010. As of today, the MAN Lion's City Hybrid has done several hundred thousand kilometres. To produce exact data, conventional vehicles of similar performance and the same payload operated a reference service. A population of around 75 Lion's City Hybrids is currently in regular service, while the large number of orders is testimony to the great interest that cities have in a technology that reduces fuel consumption and CO2 emission.
The empirical fuel-consumption values were gathered from a broad data basis, which means that figures resulting from practical operation on widely differing bus routes can be compared with those from tests and simulations. The result is clear: the serial hybrid drive is the optimum for heavy urban traffic, where the Lion's City Hybrid achieves fuel savings of up to 30 percent.
The hybrid version of the MAN Lion's City was in no way designed with low-performance heating and air-conditioning systems: the air-conditioning and heating comfort provided leaves nothing to be desired. The consumption figures prove it: even when these comfort functions are used intensively in summer and winter, the MAN Lion's City Hybrid still saves a considerable amount of fuel. Of course the savings that can be achieved are subject to a seasonal variation, peaking in spring and autumn. In other words, there are significant fuel savings under all seasonal conditions. This is proof of the optimum suitability of the serial hybrid system and of the Lion's City Hybrid's finely tuned energy management system.
40 new Lion's City Hybrid buses for pilot regions and cities in Europe
More pilot regions and cities deploy Lion's City Hybrid: in the framework of the electromobility program funded by the German Federal Ministry of Transport, Building and Urban Development, the ARGE "RegioHybrid" purchased 24 hybrid buses from MAN. These buses have been operating in Leipzig, Freiberg, Doebeln and Mittweida since autumn 2011. The criteria for subsidisation require a 20-percent fuel saving relative to a comparable bus without hybrid technology. As expected, the Lion's City meets this criterion, verified by the measurement method prescribed by the project, in a standardised test cycle. Thanks to its compliance with the stringent EEV emission standard and its controlled CRTec® particulate filter, the MAN is state-of-the-art as far as emission criteria are concerned. In addition, the Lion's City Hybrid betters the EU limit values on noise for heavy-duty commercial vehicles, another criterion for the subsidy. It even fulfils the particularly rigorous noise-emission limits required for the "Blue Angel" environmental certificate and is thus entitled to carry the "protects ENVIRONMENT AND HEALTH" label.
The City of Luebeck has five MAN hybrid buses in service. In this way, Luebeck is reducing some of the strain that air-bore emissions and noise put on its historic old city, the largest UNESCO World Heritage site in Germany.
Bus operators in Barcelona, San Sebastián and Vallandolid are currently expanding their fleets of MAN Lion's City Hybrids: by the end of 2012, 15 hybrid buses will be in operation. After exhaustive tests in regular service, Barcelona's local public transport operator TMB has ordered a fleet of ten MAN Lion's City Hybrids for the city.
The Spanish company emphasizes that above all, the vehicles produce a good return on investment. The cities have confirmed in practice that the buses can save up to 30 percent on fuel. Looking at the lifecycle costs, everything points towards purchasing hybrid buses, even under the assumption that the diesel price will rise only moderately over the next five to ten years. On top of that, the buses also run extremely reliably: San Sebastián, the first Spanish city to commission the Lion's City Hybrid as a series-production vehicle, has not seen a single relevant unscheduled workshop stop in eight months of operation. A particularly future-proof product, fuel and CO2 savings - these may be the most important reasons for purchase, but in the same breath, customers always mention the comfort features of the Lion' City Hybrid, such as its fully-fledged electric air-conditioning and the way it accelerates so smoothly and quietly, without any jerking.
The serial hybrid drive is optimal for heavy urban traffic.
Heavy urban traffic is the ideal sphere of operation for buses equipped with serial hybrid drive. The fully laden buses, twelve metres long and weighing 18 tonnes are driven at low average speeds, accelerating no end of times to between 40 and 50 km/h, only to slow down again shortly afterwards for a stop. When they decelerate, conventional buses transform their great kinetic energy to heat. By contrast, the MAN Lion's City with its serial hybrid drive recuperates that braking energy. The stored energy can be used in a multitude of different ways: as drive energy, for example, to pull away from the bus stop under purely electric power, or to switch off the diesel engine on level stretches and "sail" electrically. Or to supply the auxiliary units such as the air-conditioning system, which then cools the vehicle even when the diesel engine is switched off at stops. On average, the diesel engine is off for around 15 percent of the time on each trip.
The decisive last few percent more in terms of fuel and thus CO2 saving can only be obtained by a vehicle in which all the hybrid components were designed to harmonise exactly with each other right from the drawing board and which were then adjusted to perfection during series development. The Lion's City Hybrid employs high-performance capacitors (ultracaps) to store the energy. They meet the requirement of being able to absorb as nearly as possible all the recuperable energy of every single braking procedure - a procedure that last only a few seconds but generates a great deal of electrical energy in that time. No other storage system can absorb so much energy in so little time. And the evaluation of the buses in operation right across Europe shows that the MAN Lion's City recuperates braking energy in 90 percent of its braking. These braking procedures put no load on the service brake, meaning that the hybrid drive thus also reduces wear and tear on the brakes. The sensitive interplay between recuperation and service brake is managed automatically by the bus, the driver merely has to operate the brake pedal. However, because skilled use of brake and accelerator is mandatory for optimum fuel saving, MAN ProfiDrive® instructors put drivers through special hybrid-bus training courses.
With the automatic start-stop system, the Lion's City Hybrid reduces its fuel consumption and emissions even further. After all, city buses spend 25 to 40 percent of their operating time standing at bus stops or red lights. The figures obtained in practical testing show that the hybrid bus reduces the amount of time during which the diesel engine would normally be running with the vehicle stationary by around 80 percent.
The MAN Lion's City Hybrid is driven by two electric motors delivering 75 kW each, coupled by a summation gearbox. Together, the two motors produce a maximum torque of 3,000 Newton-metres. This is why the MAN Lion's City Hybrid can do without conventional stepped transmission. The advantages: the bus accelerates powerfully from a standing start without any interruption of tractive force until it reaches the desired speed – this makes the ride more comfortable for the passengers and driving even simpler for the driver.
When the bus decelerates, the electric motors function as generators, transforming the braking energy into electrical energy. This is stored in so-called traction energy storage, consisting of six ultracap modules mounted behind attractively formed and aerodynamically optimised panelling on the roof of the Lion's City Hybrid. Ultracaps, also known as high-power capacitors, have a number of advantages relative to the battery systems currently available: high power density, extremely fast power input, long cycle life, constant reliability and a high degree of efficiency. Unlike batteries, no chemical conversion is involved in charging and discharging - electric charges are simply shifted. The absence of moving parts and freedom from maintenance add to the high cost-effectiveness already being achieved. Memory effects and loss of power due to ageing are considerably lower in ultracaps than in lithium-ion or nickel-metal hydride batteries. Ultracaps have a much longer service life than battery systems. Operators of MAN Lion's City Hybrids will be spared the complicated and expensive process of exchanging the energy storage unit during the usual service life of a city bus - one of the great advantages that the MAN system has over hybrid buses that use batteries for transaction energy storage. The fact that batteries deliver considerably less power at low temperatures than ultracaps is another aspect in favour of the MAN system.
When running on energy from its ultracap modules, the MAN Lion's City accelerates quietly and without emitting exhaust gases: depending on the operating conditions, this can be for a distance of several hundred metres. Once the energy storage is empty, the eco-friendly MAN diesel engine mounted at the rear of the bus cuts in automatically and with the help of a generator, produces the current needed for the electric traction motors. The Lion's City Hybrid uses a small-volume MAN six-cylinder diesel engine with a capacity of 6.9 litres and an output of 184 kW (250 hp) to produce electricity. This economical diesel engine with modern common-rail injection complies with the voluntary EEV emission standard and is equipped with a controlled CRTec® particulate filter that cleans the exhaust gas of up to 99 percent of its soot. The diesel engine is operated mainly in its optimum speed range with reduced dynamic performance.
Intelligent energy management is responsible for the efficient and reliable interaction between the electric motors and the diesel engine, and between the generator and the energy storage as well as the auxiliary units. This control system was developed by MAN's own engineers and was continually optimised during the test phase. It controls the operation of the diesel engine and the automatic start-stop system, monitors the charge status of the ultracaps and regulates the operation of auxiliary units such as the power-steering pump and the air-conditioning system. Thanks to intelligent management, the system doesn't need to be configured especially for different routes or driver profiles: this guarantees that all potential efficiency is always utilised to the full.
As far as the passengers are concerned, the MAN Lion's City Hybrid offers all the advantages in terms of comfort and safety for which the conventionally powered low-floor buses from MAN are renowned. Despite its additional technological components, the Lion's City Hybrid has the same number of seats. The air-conditioning system of the Lion's City Hybrid is electrically operated and regulated by demand, so that even when the bus is stationary and the diesel engine is switched off, passengers will not swelter in the summer heat.
Intelligent energy management keeps the driver continually informed of the system's charge status and its readiness for operation. The dashboard's central display shows all the data needed for efficient, stress-free and economical operation. These include instruments showing the charge status, the current degree of energy recuperation and general diagnostic information. MAN offers special introductory courses and training for MAN Lion's City Hybrid drivers so that they can fully utilise the energy advantages of the vehicle in day-to-day operation.
Red dot design award 2011 for the MAN Lion’s City Hybrid
The MAN Lion's City Hybrid is the embodiment of efficiency in local public transport. Because its design is particularly successful in giving visual form to this efficiency, the bus was recognised with the red dot Design Award 2011. Seen from the side, the roof silhouette looks as though it has been cast in one, while a visual linkage in the colour of the vehicle accentuates the contour. A rear spoiler with modelled, flow-separation edges makes the components on the roof invisible from behind. The front view of the vehicle stresses the design of the aerodynamically sophisticated cooling-air routing through two characteristically formed air ducts.
OekoGlobe 2011: MAN Lion's City Hybrid honoured
The panel of judges for the coveted German environmental prize "OekoGlobe 2011" honoured the MAN hybrid bus with an award: MAN Lion's City Hybrid was named best bus in the category "Vehicle innovations in public transport".
Autobús del Año 2011
In Spain, the MAN Lion's City Hybrid was voted "Autobús del Año 2011". This national award was set up by the Spanish newspaper Revista Viajeros and the panel of judges consists largely of experts from various of Spain's local public transport companies. Decisive for the panel were the high potential savings in fuel and CO2 emissions and the vehicle's outstanding suitability for withstanding the rigours of everyday operation.