One bus, five innovations

MAN EfficientHybrid is a self-learning energy management system that is responsible for efficient and reliable interaction between diesel engine and energy storage device. It controls operation of the D15 diesel engine and the automatic start/ stop feature. For the first time this new technology enables the bus engine to be completely shut down at stops or traffic lights, so that fuel consumption and emissions can be reduced by up to 16 percent compared to the previous vehicle.

The core of the system is the crankshaft starter generator, an electric device that converts mechanical power into electrical energy during braking. This recovered energy is stored in an ultracap module on the vehicle's roof and provides the on-board power supply – whether the engine is running or not. The MAN EfficientHybrid constantly controls the ultracap's charge level and regulates operation of the auxiliary units. Even at a standstill: because buses are immobile for between 25 and 40 percent of their operating life – mostly at bus stops or red traffic lights. Seen over the service life of an urban bus, that is 2.6 million start-stop operations involving engine and energy storage device. This results in lower CO2 emissions than with conventional diesel engines.

MAN has been researching hybrid bridge technology since the 1980s. It helps reduce emissions until electric buses are mature enough for continuous use. MAN has many years of experience of using electric powertrains and components. The first series of the MAN City Hybrid rolled off the production line from 2011. At that time MAN relied on a modular concept that enabled both the charging technologies and the number of energy storage modules to be selected and combined as necessary depending on the required range and transport capacity. MAN has since launched a new, improved technology on the market: MAN Lion’s City urban buses can now be optionally equipped with MAN EfficientHybrid. This version is significantly more efficient compared to the conventional hybrid bus.

MAN EfficientHybrid also introduces an intelligent energy management system into the new MAN Lion's City. A bus like this has needs: ventilation system, lighting, power-assisted steering, door opener, loudspeaker system – all of them electric. The system retains an overview and efficiently distributes the demanded and retrieved quantities of electricity within the vehicle – and it learns. Its intelligent control system means the bus doesn't have to be configured for different routes or driver profiles. MAN EfficientHybrid continuously optimises the most sustainable consumption mix, controls energy storage and recovery and ensures operational capability of the peripherals.

Yet the goal remains: a bus without exhaust fumes. Hamburg wants to purchase only emission-free buses from 2020, for example. MAN therefore formed a development partnership with Hamburg Hochbahn and the Hamburg-Holstein transport operators. MAN is also a member of the 26-strong ECOCHAMPS consortium. This is promoting the development of an efficient, compact, durable and cost-effective hybrid powertrain for various purposes under the umbrella of the EU "Horizon 2020" project. And ultimately the production of pure electric vehicles at MAN is imminent. The MAN Lion's City E goes into series production in our Polish bus plant in Starachowice from 2020. This intelligent bus will make cities cleaner in the future.