eMove360°: intech retrofits old diesel buses with electric drives

It is a collaboration that could quickly bring relief to cities burdened by emissions: The Garching-based digitalization, software specialist, and automotive supplier In-Tech and ZF Aftermarket are launching a strategic cooperation to reduce greenhouse gas emissions. The focus of the partnership, involving a mixed team from the two dissimilar companies, is the conversion of conventionally powered public transport buses to environmentally friendly electric drive using a retrofit kit called e-trofit. ZF Aftermarket contributes the necessary vehicle components as a system supplier and provides access to the global workshop and service network. The conversion, featuring an electrically driven axle from ZF and a roughly 1,000-kilogram lithium-ion battery from Garching-based specialist Invenox with a capacity of 320 kWh, is expected to take a maximum of four weeks.

Roof Storage: Sophisticated Batteries with High Energy Density and Long Lifespan

The energy storage units will be housed in the roof area. Their cells are clamped, not welded, to simplify maintenance and reduce manufacturing costs. Further innovations of the Garching batteries using the so-called Conchifera technology include a pole contact cooling system for longer lifespan, an integral design for high energy density, and the option to use standard battery cells of type 18650. The retrofitted buses' range in the "worst case" scenario is expected to be around 200 kilometers, as In-Tech spokesperson Christine Oertel emphasized at the exhibition booth. "We are thus considering high summer or winter operation, when the air conditioning or heating is running at full blast," the spokesperson further elaborates. Additionally, the battery capacity can be adjusted in steps of 40 kWh depending on individual requirements. This flexibility allows the realization of bespoke small series, which is not possible with large manufacturers. The elimination of the rear engine also creates space for auxiliary units and control electronics. "Of course, the conversion also takes into account the changed axle loads due to the battery and auxiliary units," assures Oertel.

Pilot Vehicle Stadtwerke Landshut: Longest Line as a Benchmark

In the pilot project with Stadtwerke Landshut, where a 15-year-old Mercedes-Benz Citaro bus was converted, the line operation was analyzed in practice, and the longest route was taken as a benchmark for the configuration. "In general, we can adapt the retrofit kit to the specific needs, which vary in each city," Oertel further promotes the concept. The possibility of interim charging can also be considered when determining battery size. In Landshut, the configuration is based on overnight charging of the vehicle at the depot, ensuring a full day's operation. The system also integrates a telematics module to monitor the operating condition of the components. "Additionally, we naturally have the option of onboard Wi-Fi as a comfort feature for the passengers," adds Oertel.

Cost Factor: Upcycling at Half the Price of a New E-Bus

The provider estimates costs of around 350,000 euros for the elaborate conversion. "That is about half the price of a new electric bus. Over ten years, however, the provider calculates a fuel saving of 100,000 euros and also points to significantly lower maintenance and service costs. In addition to reduced CO2 emissions and the elimination of fine dust and nitrogen oxides, the manufacturer also highlights the aspect of 'upcycling.' 'Of course, we also conserve resources by refurbishing older buses,' explains Oertel. This ranges from the overhaul of the chassis and brakes to cosmetic repairs and a complete new interior fitting.

Not Just Tomorrow: Available from 2019

For Helmut Ernst, head of the Aftermarket division, e-troFit comes at just the right time: "The markets will not be ready until 2025 to provide the necessary capacities of electrically powered vehicles in series production. To still achieve the required climate protection targets, converting conventional commercial vehicles to electric drives by then presents an excellent opportunity," says the ZF expert. in-tech also reports great interest from municipalities and public utilities, as well as airports signaling their interest. Furthermore, an Austrian freight forwarder has requested the conversion of a Mercedes-Benz Actros to an electric retrofit drive. This project is currently being implemented. The electric kit is scheduled to go into series production in mid-2019.