Retrofit electric drive kit for diesel delivery vehicles
By integrating an electric drive the retrofit electric drive kit (EleNa) transforms delivery vans with diesel engines into a hybrid vehicle that runs solely on electric power for short journeys. The retrofit kit was developed as a prototype within the framework of a joint research project funded by the German Ministry for traffic, construction and urban development BMVBS.
Up until now the delivery vehicle chosen for the project was powered by a 2.2 litre four cylinder diesel engine with 95 kW (129 HP ) with a maximum torque of 227 Nm. The VECTOPOWER electric motor is new. In addition, the highly efficient asynchronous motor provides a continuous output of 60kW and a maximum torque of 458 Nm via a gear unit on the cardan shaft.
Sketch of vehicle with retrofit electric drive kit
The asynchronous motor is driven by a VECTOPOWER inverter. Both components are optimally matched to one another. This creates a highly effective very compact system that makes ideal use of the limited space in the vehicle. Together with the powerful battery the transporter has a range of 50km with pure electric drive even with a full load. The maximum speed is 120 km/h.
In order for a hybrid drive to function properly the interaction between the combustion engine and the electric motor must function smoothly. The control unit developed by the Huber group fulfils this task excellently. This is also proved by the dynamic acceleration of the diesel delivery vehicle:
Acceleration behaviour with fully loaded vehicle
Another hurdle in hybrid vehicles is the availability of ancillary units when only the electric drive is in operation. For this reason ancillary units such as power brakes and power steering were substituted and a second cooling circuit was implemented.
The parallel hybrid design allows four different operating modes:
- In the default mode the transporter is powered only by the combustion engine. The electric motor is decoupled.
- In the boost mode the driver can utilize the combustion engine and the electric motor.
- The highlight is the purely electric mode. Here, the transporter is driven only by the electric motor. Ideal for stop-and-go traffic in cities.
- In charging operation the electric motor runs in tow. As a result, the asynchronous motor functions as a generator and produces electrical power for charging the battery. Charging operation makes sense on overland trips for example.