Hybrid electric bus

The hybrid bus is a bus and belongs to the class of hybrid electric vehicles. They are equipped with a plurality of drive systems. For example, you over an internal combustion engine with an electric generator or a fuel cell as a power generator, electric motor ( s) and a traction battery.

The term " hybrid" is derived from the Latin term hybrida Greek origin and means something crossed, mixed or bundled. A hybrid vehicle is defined by the UN, a vehicle in which at least two energy converters and two built- in vehicle energy storage systems are in place to drive it. Energy converter, for example, electric, petrol and diesel engines, energy storage, for example, battery or fuel tank.

Unlike Duo buses hybrid buses are independent of overhead lines, the diesel engine is used for continuous power supply, the power generated in both flows into the electric motor that actually drives the axles than in the current memory. Peaks in energy consumption - at take-off - are supplied from the power storage. As regards their type is usually, for example, in modern fuel cell buses to serial hybrids, in which the internal combustion engine is no longer directly drives the vehicle.

• 4.1 Hybrid buses at German transport companies
• 4.2 Hybrid buses at Swiss transport companies

Pros and Cons

The aim of the system is next to a better driving dynamics in a reduction of fuel consumption and pollutant, noise and CO2 emissions. This can be achieved by a better starting and acceleration characteristics with operation of the diesel engine in the optimum speed range and on the other by braking force recovery.

Disadvantages of the system are space and weight of additional technical equipment. In a placement of components on the roof of buses, like with most test objects, this needs to be strengthened and the dynamics of the bus must be adapted to the increased gravity. At lower temperatures must, due to the lower drive loss (waste heat), additional energy for the heating of the bus to be applied. This reduced under these conditions, the efficiency advantage of the system.

Parallel and serial hybrid drive technology

There are two fundamentally different hybrid drive technologies.

In the parallel hybrid technology, both types of drives at the same time access to the drive train. The electric drive works here mostly supportive. The combustion drive runs permanently. This technique is except for city buses used in local buses, which have a greater average speed and a longer distance between stops.

In series hybrid technology generator is first powered, or to a fuel cell generates electric power, which is temporarily stored in a traction battery from the engine. The engine can be operated uniformly at the optimum speed range. Also, the fuel cell must be regulated slowly, which increases the service life of the fuel cell stack. One or more electric motors drive the wheels. Driving is done purely electrically. This technique is used especially in city buses that reach at short distances between stops and higher traffic density and a low average speed, but require more frequently and have to brake.

Manufacturers and models

From the company Daimler -Benz in 1996 a pre-series (MB O 405 GNDE ) was produced as a low-floor bus with wheel hub motors. The development was stopped, however. Daimler Buses North America has delivered more than a thousand buses.

Currently produced EvoBus the Mercedes -Benz Citaro G BlueTec Hybrid. This is designed as a serial hybrid. That is, a diesel engine fed by a generator, a battery. This battery powers the electric traction motors with power. Due to the smoother operation of the diesel engine, as well as the recovery of braking energy can, in spite of several energy conversion, a reduction in consumption can be achieved.

From this derived the Mercedes -Benz Citaro FuelCELL hybrid is from 2011 as the third version of the fuel cell buses. The electric power for the drive motors provides here with the battery, a fuel cell instead of a diesel engine with a generator. By storing braking energy in the batteries and a load- independent operation of the fuel consumption can be reduced by. This allows the tank volume to be 35 kg, compared to 45 kilograms of a Citaro FuelCell reduced. The batteries have a capacity of 27 kWh. The electric drive is transmitted to wheel-hub motors with a total output of 120 kW. Ten 12 -meter Citaro FuelCell Hybrid will be tested in 2011 in Hamburg in regular service of the Hamburg elevated railway. Worldwide are 21 more of these city buses are being tested in various other cities. EvoBus expects to start the series Manufacture taking place from 2015 and 2020.

MAN

Mid-2007, a vehicle was presented based on the MAN Lion's City with hydrogen internal combustion engine. These vehicles were from July 2007 in the sample used in the Berlin transport. However, this field experiment did not go smoothly, as the buses in comparison were not very reliable. From 14 buses in early 2009, only four were operational. Another pilot project started in August 2005, between Franz Josef Strauss Hallbergmoos and Munich Airport ( bus 699 ). Currently (2012 ) there are no projects with more hydrogen internal combustion engine.

Since 2010, with the Lion 's City Hybrid hybrid forth. The first of these vehicles was placed in service in Munich.

Hess Vossloh

Also in July 2007, was presented with the Hess lighTram hybrid of the first double-articulated hybrid and tested in train.

Since May 2011 ( numbers 495-499 ) five 18m hybrid articulated buses of Hess / Vossloh Kiepe are used in the Leipzig and Dresden transport companies as well as in urban transport Lübeck.

The Dresden Transport test in January 2007 a ​​Solaris Urbino 18 Hybrid, which will be used on the line 82. More buses of the same type have been running since mid- 2007 as the first Hybridbustyp in Switzerland at the region Lenzburg, since the fall of 2007 at the Leipzig transport operators and, since January 2008 at the Bochum- Gelsenkirchen trams AG.

On 13 September 2008, the first hybrid articulated bus was presented with a closed diesel particulate filter of the company Solaris Bus operation at the Munich Josef Ettenhuber in Ottobrunn. He comes since the regional bus services of MVV used. Together with the MVV, the company Ettenhuber checked out the bus over four years to its economy.

Volvo

Volvo introduces its city bus model 7900 her only as a hybrid with the same drive. The previous 7700 arose first with normal diesel engine.

Wrightbus

The Irish bus manufacturer Wright delivered in 2006, the first six copies of a single-deck hybrid bus for Go-Ahead London. The hybrid drive has since been further developed and these buses are called " Electro City " marketed.

In addition, is still produced another double-decker hybrid bus Wrightbus with the New Bus for London ( NB4L ). The Transport for London (TfL ) georderte Busserie - first 600 cars - will be made ​​available to the operators determined by tenders available. 2013 already wrong on four lines NB4Ls.

Alexander Dennis

The British company Alexander Dennis Ltd.. (ADL ) produced in Scotland since 2008 hybrid buses in all sizes from Midibus ( Enviro 200 H ) to the three-axle double-decker bus ( Enviro 500 H). The ADL Enviro 400 H with the serial drive is the most-produced hybrid double- decker, it is available in various lengths as a two-axle bus. Especially the large double -decker type Enviro 500 H are also produced for markets outside of the kingdom, next to Hong Kong and Australia also in left-hand drive version for North America and Europe as tour buses.

Optare

The UK subsidiary of Ashok Leyland is the low-entry bus Optare Tempo ago, which is also available in a hybrid version since 2008.

Bredamenarinibus

In Italy, the company offers Bredamenarinibus the 12-ton electric - diesel hybrid Bredamenarinibus M 240 El on for 88 to 97 passengers.

Voith Turbo

Dissemination

Hybrid buses at the German transport companies

Overall, the German transport companies operate 204 hybrid buses ( the 13 May 2012). Largest operator was there with 18 vehicles, the DVB AG followed the Bogestra with 15 In NRW, the most were 81 hybrid buses represented in a state, followed by Saxony with 46

When Bogestra run fifteen Solaris Urbino 18 Hybrid. The DVB is a Solaris Urbino 18 hybrid, three Hess BGH N2C Vossloh Kiepe hybrid buses and eight Mercedes -Benz Citaro G BlueTec Hybrid buses. The Hamburg elevated railway sets since 2010, a hybrid buses. The subsidiary of the HHA Jasper and Süderelbebus GmbH (SBG ) Volvo 7700 and 7900 are used, the VHH set since December 2013 a Volvo 7900. The LVB is a Solaris Urbino 18 Hybrid in use. The MVG in Munich employs two hybrid buses, a Solaris Urbino 18 Hybrid as well as a MAN Lion's City Hybrid. The MVG Mainz sets since May 23, 2012 a tentative Mercedes -Benz Citaro G a. The SSB has expanded its fleet by three Mercedes -Benz Citaro G BlueTec ® Hybrid in September 2010. Two more were to follow later in 2010.

The Stadtwerke Krefeld SWK use four Mercedes -Benz hybrid buses and plan for 2011, four hybrid waste collection vehicles use. In the yard of the KVB has two MAN Lion's City Hybrid. In March 2011, three hybrid Citea SLF120 were delivered to the HEAG mobibus in Darmstadt. The five Citaro G articulated hybrid buses the Rostock Tramway AG were traded for unsatisfactory availability to conventional Citaro G.

Hybrid buses at Swiss transport companies

Various Swiss Transport Authority ( BVB, TL, STI, BSU, SBW, TPG PAG) added 2011/12 tentatively in the scheduled operating a Mercedes Citaro G Blue Tex and a Hess SwissHybrid. The fuel savings achieved an average of less than ten per cent, in Winterthur was due to the small distance and stops comparatively viscous transport not registered savings. In contrast, a noticeably lower noise pollution has been registered. In principle, consumption slightly better cut of the Citaro with lithium -ion battery opposite the Hess with Super Caps from

Since October 2012, at La Chaux -de-Fonds seven Solaris Urbino 18 Hybrid (No. 341-347 ) to replace the trolleybuses successively.