|The Vito E-CELL van. Click to enlarge.|
Mercedes-Benz is introducing the Vito E-CELL electric van. Production of a small series of 100 Vito E-CELL vans has already begun, and a further 2,000 units are planned from 2011. The van, targeted for inner-city operations and for particularly environmentally sensitive areas, is based on the long-wheelbase Mercedes-Benz Vito with a standard roof. The long wheelbase of 3200 mm provides the necessary underbody space for the traction batteries.
With an operating range of around 130 km (81 miles), the Vito E-CELL meets average customer requirements for a daily van mileage of approx. 50-80 km (31-50 miles). Payload is around 900 kg (1,984 lbs) depending on equipment specifications, and the van has a top speed of 80 km/h (50 mph), making it also suitable for short inter-urban stretches.
|The Vito E-CELL. Click to enlarge.|
The Vito E-CELL is propelled by a permanent synchronous electric motor that develops a continuous output of 60 kW and a peak output of 70 kW. Maximum torque is 280 N·m (207 lb-ft). As the full torque is inherently available right from the start in electric motors, the Vito E-CELL delivers performance at the familiar level of modern diesel engines.
Power is transferred to the front wheels via a single-speed transmission developed specifically for the Vito E-CELL.
To save installation space for the batteries, and in contrast to the other models in the Vito series, the vehicle has front-wheel drive. With the exception of a few suspension components adopted from the Vito 4x4, the front-wheel drive system was specially developed for the Vito E-CELL.
|Motor and power electronics are packaged under the hood. Click to enlarge.|
In addition to the electric motor, other components such as the power electronics, transformer and the grid charging unit are accommodated beneath the engine cover. The 12 V onboard network was also completely newly developed.
The Li-ion batteries are housed under the load compartment floor, where the propshaft and fuel tank are usually located in the Vito. The batteries feature high performance and load capacity, a high energy density and a nominal voltage of 360 volts. Total capacity of the battery pack is 36 kWh, of which 32 kWh (89%) are available to power the vehicle.
The battery pack of the Vito E-CELL consists of 16 modules with a total of 192 cells, each cell being monitored by a battery management system. To avoid unnecessary power losses and the risk of damage caused by unauthorized persons when the vehicle is parked, a safety system (“Watchdog”) deactivates the high-voltage network when not in use.
The batteries, electric motor, converter and other electrical components of the drive system are water-cooled. For driver comfort during the colder months of the year, the Vito E-CELL is equipped with a heater booster. This is connected to the high-voltage network and the standard heating circuit in the instrument panel.
The batteries are charged at charging stations provided to the pilot customers by the two energy providers EnBW and Vattenfall. These companies are participating in the customer trials as cooperation partners in the Berlin (Vattenfall) and Stuttgart (EnBW) regions. The charging stations are installed on the business premises of the fleets involved. The charging socket of the Vito E-CELL is connected to the station using a standard seven-pin charging cable.
The batteries of the Vito E-CELL are charged at 380/400 volts; the onboard chargers have an output of 6.1 kW. Charging takes a maximum of six hours if the batteries are fully discharged. Using an additional charging cable with a conventional domestic power plug, the Vito E-CELL can also be charged from the 230 volt mains if required. In this case the charging time is doubled, however.
The batteries are also charged by energy recuperation while on the move, i.e. by regenerative braking, on the overrun and when reducing speed. All this is in interaction with the new ESP system.
The Vito E-CELL features a Smart Charge Communication Unit (SCCU) as standard, enabling smart charging. The charging units can be individually set at the multifunction steering wheel and in the instrument cluster to charge for times when low-cost electrical power is available. This can also be done centrally on a PC by the scheduler. The SCCU also allows parallel charging of several vehicles in a fleet, without overloading the grid.
Vehicle availability can also be calculated depending on the charge status of the batteries. A scheduler is able to call up the charge status and therefore the available operating range of the Vito E-CELL on a computer screen, and determine whether a particular van is able to carry out an additional assignment at short notice.
More than a dozen Vito E-CELL vans have undergone extended test drives both on enclosed test tracks and on the roads.
Mercedes-Benz will deliver 100 Vito E-CELL vans to customers between August and December this year. Half each will be taken into operation in Berlin and Stuttgart, and further units will be used in the Basque region of Spain early next year.
Although all densely populated, these areas not only differ in size but also in topographical terms, ensuring different operating conditions and therefore additional findings. Initial customers are predominantly fleet operators.
The customer trials for the Vito E-CELL are scheduled for four years and roughly 80,000 km (49,700 miles) per vehicle, after which the 100 vans will be returned to Mercedes-Benz. For this reason the customers are not purchasing their vehicles, but rather renting and financing them by paying a monthly user charge which also includes all the servicing for the Vito E-CELL.
Ideally the 100 Vito E-CELL vans will cover a total of around eight million kilometers (4.97 million miles) in roughly one dozen fleets during the customer trials, providing data and experience to support the further development of electric drive systems in light commercial vehicles.
In parallel with the practical trials, Mercedes-Benz will evaluate data such as route profiles, operating ranges and other parameters in order to tailor electrically powered vehicles even more precisely to customer requirements.