Empa, ETH Zürich and the road sweeper manufacturer Bucher Municipal have jointly built a pioneering hybrid-electric powertrain for road sweepers, as part of a Commission for Technology and Innovation (CTI) project. The concept is based on a natural gas engine, which provides power to the electric motors. Compared to conventional sweepers, the energy consumption has been halved and CO2 emissions reduced by more than 60%. Bucher Municipal is currently working on a concept study to explore possible commercialization of the new technologies.
The project goals were ambitious: the energy consumption compared with today’s diesel vehicles was to be reduced by 45% and the total costs of the vehicle (purchase, interest, operating costs) were not allowed to exceed the costs of the current technology. To achieve this, the researchers and engineers have replaced conventional hydraulic power distribution with more efficient electric drive systems. Instead of a diesel engine with a hydraulic pump, a small gas engine with a power generator now acts as the drive source.
The hybrid drive system has a modular design. This means that a petrol, LPG or diesel engine could be installed instead of a natural gas engine. If a hydrogen-powered fuel cell or a significantly larger battery is used instead of an internal combustion engine with power generator, purely electrical operation would also be possible. This modular drive concept will allow Bucher Municipal to cater for a wide range of different customer needs in the future.
The management of Bucher Municipal is planning to further develop the electric hybrid drive’s modular platform and has already launched an internal concept study to this end. In this context, further work on reducing costs, optimizing operation and packaging must be carried out in the areas of the power battery, the onboard power generator and the overall vehicle. In parallel to this, the production processes will be analyzed with regard to vehicle electrification.
Source: Empa (Swiss Federal Laboratories for Materials Science and Technology)