Volkswagen to enter next phase of hybridisation with 48-volt mHEV

Volkswagen will enter the next phase of the hybridisation of its drives with the new 48-volt mild hybrid drive (mHEV) combined with the 1.5-l TSI evo petrol engine. Volkswagen will be showcasing its progress toward integrated, CO₂-neutral mobility at the 40th International Vienna Motor Symposium (May 16-17). 

Volkswagen has revealed that the new 48-volt system will join the conventional 12-volt vehicle electrical system. The 48 volts power the belt-integrated starter generator (BSG), 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 BSG 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 BSG and support the TSI.

Other smart functions in the BSG 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.

Volkswagen believes that the most efficient way to reduce CO2 emissions is to expand battery electric vehicles (BEV) on a broad scale. The MEB will form the basis for the next generation of electric vehicles. The electric platform’s key features are its high-voltage battery (installed in the underbody to save space), its compact electric drive on the rear axle (or alternatively on the front axle), and its standard CCS system for quick charging. It also forms the basis of the new end-to-end all-electric “E” architecture along with the ‘vw.OS’ operating system, which can be used to establish new mobility services and assist systems. In other words, Volkswagen is evolving from a pure vehicle manufacturer into a mobility provider while also creating the conditions required for automated driving.

As part of its large scale industrialisation of electric drives, Volkswagen is widely promoting its MEB’s primary drive on the rear axle and uses a permanent magnet synchronous motor. It is characterised by high power density, a high level of efficiency and consistent performance across a broad speed range of 16,000 rpm.

Volkswagen claims that it began developing assist functions more than 20 years ago and now offers a wide range of driver assistance systems for longitudinal and transverse vehicle control under its ‘IQ.DRIVE’ umbrella brand. These systems are the first steps on the journey to automated and, ultimately, driverless driving. In the future, autonomous vehicles will be active on the roads and in a wide range of domains, including motorways and multi-storey car parks. Vehicles will gradually take over more and more tasks from drivers.