Energy management strategy and auxiliaries

Today auxiliaries account for 15% to 25% of the total energy budget of an internal combustion engine (ICE) bus, but they can rise up to 50% in the case of electric propulsion with no excess heat energy to exploit. Thus, requirements for energy management for different propulsion technologies can vary, and so do the optimal solutions. Energy management strategies to be exploited within EBSF_2 are based on both real-time and anticipation of the near future operating profile. This predictive component is based on schedule, the vehicle’s en-route position, street geometry and topography, and enables more adaptive and higher-level system control than traditional real-time but algorithm-based control. Solutions for new buses, especially electric buses, are considered very promising but many solutions can be adapted also for retrofitting of buses already in operation. It is therefore important to keep the additional hardware cost as low as possible.
Heating, ventilation and air conditioning (HVAC) are an important area for improvement in both ICE and battery-powered buses due to their high power needs. A combination of measures can increase the efficiency of air conditioning units as well as reduce heat loss via the interior and exterior design of buses. Effective circulation of air could also help maintain a comfortable temperature inside the bus with less energy input. Fresh air is required to control moisture/condensation on window surfaces which is imperative especially during snowy winter conditions. Solutions related to the bus stop events, such as controlled door openings for less heat exchange or a totally indoors bus stop, offer a major step-up from today’s technology level. Improved HVAC systems that can use 20 to 30% less energy will be tested in different climate conditions.