Orion Buses and Freightliner Trucks

The Daimler subsidiary Orion in North America is the globally undisputed market leader for hybrid buses. Since 2003 the brand has been awarded contracts to deliver the Orion VII HybriDrive city bus to numerous cities in Canada and the U.S., including New York and San Francisco. More than 1,100 of these convenient low-entry vehicles are now in everyday use, and a further 1,500 buses have been ordered. The current fleet of Orion hybrid buses are driven approximately 50 million kilometers each year.

The Orion VII HybriDrive is equipped with a series hybrid drive, in which the diesel engine is always in operation. The engine transmits power to a generator, which, in turn, drives an electric motor that is located directly behind the rear axle. Drive power is exerted onto a conventional drive axle with a differential. The compact diesel engine is transversely mounted in the rear of the vehicle. The 5.9-liter engine generates 191 kW (260 hp) and is equipped with a particulate filter. The electric drive motor delivers 184 kW (250 hp), and can even achieve 235 kW (320 hp) for brief periods.

The Orion VII HybriDrive consumes about 20 to 25 percent less fuel than conventional city buses. Compared to diesel-powered buses without filters, particulate emissions are reduced by 90 percent, while nitrogen oxide emissions are cut by 40 percent and carbon monoxide emissions by about 30 percent. When viewed over an average service life of 12 years, each bus saves about 75,000 liters of diesel fuel and prevents about four tons of nitrogen oxides and almost 200 tons of CO2 from being emitted into the environment.

One remarkable aspect is that the Orion hybrid buses used in New York have shown themselves to be more reliable than conventional diesel-powered buses. Thanks to their electric drive systems, the hybrid buses accelerate more quickly and quietly. In addition, the brakes last twice as long, and the diesel engine and electric motor promise to have an extremely long service life.

In North America the Daimler Trucks brand Freightliner not only develops conventional trucks, but also commercial vehicles with parallel hybrid drives. The most recent example of this is the medium-duty M2 Hybrid truck with 15 tons GVW. The vehicle was especially designed to meet the conditions in North America, where “cherry-picker” service vehicles play a key role in maintaining the many overhead power lines. That’s why Freightliner not only uses the drive system’s electric motor as an alternative and a support to the diesel engine, but also as a quiet, zero-emission power source for the accessory unit for operating the boom lift. The system can also be used to power other similar drives such as those used to operate the pumps of tank trucks or firefighting vehicles.

The M2’s drive system combines a compact Mercedes-Benz 6.4-liter six-cylinder inline engine delivering 186 kW (252 hp) with an electric motor that has a peak performance of 44 kW and a maximum torque of 420 Nm. Power is supplied by lithium-ion batteries that are recharged by a regenerative braking system. The parallel hybrid system can achieve fuel savings of between 25 and 30 percent.

The Freightliner M2 Hybrid has been successfully tested since the summer of 2006. Because the innovative truck concept is so effective, Freightliner is now planning to produce a total of 1,500 of these vehicles.

Cargo vans are often used to deliver goods to businesses and homes in areas that are particularly sensitive to emissions, such as residential areas and pedestrian zones. North American parcel delivery services employ these vehicles in large numbers. The Freightliner subsidiary Freightliner Custom Chassis Corporation (FCCC) manufactures thousands of chassis each year for such delivery vehicles. The vehicles are conceived as walk in vans, whose design and equipment are tailored to the needs of American delivery services.

One version of this van is a parallel hybrid that has been successfully field tested by a major customer for more than three years. During this time, the 25 test vehicles have achieved excellent results, including big fuel savings and a high level of reliability that is expressed by a 99-percent availability rate. Due to this success, Freightliner will now deliver 75 additional vehicles. The van with 7.3 tons GVW has a parallel hybrid system that combines a 4.25-liter four-cylinder diesel engine delivering 125 kW (170 hp) with a 44 kW electric motor. The electrical power is stored in lithium-ion batteries.