Volkswagen presents the mHEV architecture in Vienna
Levels 3 and 4 of automated driving, a 48-volt drive system and a platform developed exclusively for e-vehicles – Volkswagen will be showcasing its progress toward integrated, CO2-neutral mobility at the 40th International Vienna Motor Symposium.
The mild hybrid (mHEV) system makes an important contribution to sustainable mobility. Depending on the driving style, it can save around 0.4 litres of fuel over 100 kilometres and cut carbon emissions in the process. Volkswagen will enter the next phase of the hybridisation of its drives with the new 48-volt mild hybrid drive combined with the 1.5-l TSI evo petrol engine. This will see a 48-volt system join the conventional 12-volt vehicle electrical system. The 48 volts power the belt-integrated starter generator (in German Riemenstartergenerator, RSG), which is located where the alternator used to be in the auxiliary drive. It controls two central operating statuses: recuperation and boost.
During recuperation (brake energy recovery), the RSG acts an alternator that is able to absorb some of the vehicle’s kinetic energy. The recovered energy is stored as electrical energy in a separate 48-volt lithium-ion battery located underneath the front passenger seat. This energy is released during the electric boost to power the RSG and support the TSI.
Other smart functions in the RSG assist the TSI engine during the startup process, taking on the role of the pinion starter. This helps to save fuel and makes the start process even easier.
The mHEV also includes the now familiar eco-coasting function. This mode allows the vehicle to “coast” with the engine switched off so that no emissions are produced, an important factor in the drive’s ability to reduce fuel consumption by 0.4 litres per 100 km. Linking the 48-volt network and the rest of the vehicle electrics is a DC/DC converter, which converts the 48 volts into 12.