Reference report: EleNa Electric drive retrofit set

With the installation of an electric drive, the ELENA retrofit set eco-nomically converts delivery vans with a combustion engine into hybrid vehicles that can drive short distances solely with electrical power.

The idea

Creating a delivery van that can drive around town with zero emissions and is simultaneously equipped for long-distance trips is the objective of ELENA, a project funded by the “Electrical Mobility Model Region” of Stuttgart. The partners in the project have developed an alternative drive for everyday use in the form of a retrofit electric drive for delivery vans with conventional diesel engines. This electric drive retrofit kit is especially suit-able for all small and medium-sized enterprises to gain quick access to electrical mobility, with a low investment barrier and independently of the medium- to long-term strategies and plans of automobile manufacturers.

When a van has an integrated ELENA solution, the electric motor and the combustion motor act on the electric drive train together. This parallel hybrid drive combines the advantages of both drive ver-

sions: the electric traction drive makes it possible to drive within a town and region with zero emis-sions. At the same time, however, the conventional diesel drive is available for inter-regional trips.

This retrofit set was specially developed for the high-volume model of the Mercedes-Benz Sprinter, without the involvement of the Daimler company. The designers took particular care to ensure that the installed retrofit components are completely removable. As a result, the set can be used in leasing vehicles, for example.

battery

battery

battery

inverterelectric motor

gearbox

gearboxdiesel enginecardan shaft

Figure 1: Sketch of Sprinter with EleNa retrofit solution

A cooperation network of industry, service, research and education has joined forces for the ELENA project. Each involved party contrib-utes their expertise in order to achieve an optimum and practical retrofit solution.

As a specialist for tailor-made electric drives, ARADEX AG has developed the electric drive for the retrofit set. The components, inverters and electric motor have been perfectly coordinated by the developers. This increases the efficiency and performance of the drive. At the same time, it makes it possible to design very compact compo-nents. This is necessary because the narrow space conditions in the vehicle require a space-saving solution.

The Sprinter is powered by a diesel engine with95 kW (129 HP). The asynchronous electric motoralso provides a continuous output of 60 kW for thevehicle drive via a gear unit on the cardan shaft.The integration of the ELENA components in thedrive train is shown in figure 1. The structure is thesame as that of a parallel hybrid vehicle, i.e. thecombustion engine and the electric motor act onthe drive train together. Depending on the operat-ing mode, the torques of the individual drives areavailable simultaneously or individually. The powerelectronics are adapted to the characteristics of the diesel engine to guarantee an optimum interac-tion between the combustion engine and the

electric motor. The control unit developed by the Huber Group keeps the intervention in the vehicle electronics to a minimum. The installation of the other components only requires slight changes to the vehicle as well.

The components of the retrofit set are installed onthe bottom of the vehicle. The electric motor and the power electronics are attached next to the car-dan shaft. The battery is divided into three pack-ages. The installed batteries have a total capacity of 16.8 kWh and a weight of 125 kg. With purely electrical operation, this is currently sufficient for a distance of approx. 50 km. It is planned to charge the battery via a CEE three-phase connector (400V / 32A). The entire development is accompanied by TÜV Süd, the German certification authority. The final version of the retrofit set is to have a general type approval.

The solution

The models The parallel hybrid design allows four different operating modes, which all have their own advantages.

IC mode

In the default mode, the electric motor is decoupled. The vehicle is only powered by the combustion engine. The delivery van has its usual long range and naturally with a corresponding CO2 emission.

Hybrid mode

In the second operating mode, the electric motor is connected to the cardan shaft via the gear unit. If necessary, the driver can additionally utilize the output of the electric motor. The electrical boost can be used for passing maneuvers, on steep ascents and when starting the vehicle, for example.

Electric mode

The highlight is naturally the purely electric mode. Here, the Sprinter is only driven by the electric motor. The necessary power is provided by the battery, and the Sprinter drives emission-free. Stop-and-go traffic within a town, for example, can be managed with only electric power. This saves a consid-erable amount of diesel. The electric drive also scores points with speed: When the electric motor takes over the traction drive by itself, the Sprinter reaches a maximum speed of 130 km/h.

Charging mode

The fourth mode is especially practical, since the electric motor runs in tow. As a result, the asynchronous motor works as a generator and produces electrical power that is used to charge the battery. Charging can be done on long-distance trips, for example. During such trips, the power required to operate the generator is produced at the optimum operating point of the diesel engine and fed back to the battery. In this way, the driver can charge the vehicle batteries on the highway, for example, and then drive to his destination emission-free once he arrives in town.

The ELENA retrofit set combines the range advantages of a combustion engine vehicle with the possibility of driving emission-free. The ELENA solution is beneficial especially in urban traffic!

„...this enables a fast change over to new electric drive technology.“

Mark Oliver Utz

ARDEX AG

Figure 2: Control panel for switching between operating modes. From left: IC mode, electric mode (active), hybrid mode

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„Electrical Mobility“ Model Region of Stuttgart The region Stuttgart is one of eight german “Model Regions for Electrical Mobility”, which won a contest organised by the Ministry for Traffic, Construction and Urban Development (BMVBS). “Model Regions for Electrical Mobility” is a subsidised programm of the BMVBS, funded with115 million Euros from the second economic package.

The support programm is coordinated by the NOW GmbH - Nationale Organisation of Hydrogen and Fuel Cell Technology. Thanks to a request by the Economic Development Committee - supported by the Baden-Wuerttemberg Environment Ministry – the financial support of the federal government was awarded for different pilot projects.

Highlights

+ drive within a town and overland with zero emissions

+ the diesel drive is available for longer trips

+ completely removable

+ top speed with e-drive 130km/h

+ compact components for space-saving

+ Elektro-Boost-Function

The cooperation partners

+ ARADEX AG

+ FKFS Forschungsinstitut für Kraft- fahrwesen und Fahrzeugmotoren Stuttgart

+ Fraunhofer IPA

+ Heldele GmbH

+ Huber Automotive AG

+ IBZ, Hochschule Esslingen

+ J. Eberspächer GmbH & Co. KG

+ Kompetenznetzwerk Mechatronik BW e.V.

+ Lauer & Weiss GmbH

+ Telemotive AG

+ TÜV SÜD Automotive GmbH

+ WSEngineering GmbH & Co. KG

Interested? Give us a call: ARADEX AGZiegelwaldstr. 3 D-73547 LorchTel.: +49 (0) 71 72 - 91 81 0

sales@aradex.com www.aradex.com