VW's future: 48V hybrids
Electrifying combustion engines will be key to keeping them relevant in a world that hates emissions of any kind, and 48V hybids are the key
Volkswagen will gradually electrify almost every vehicle in its range, partly to help it meet emissions targets and partly to help people forget the diesel-gate mess. The company's first look at the future of electrified drive systems comes at the International Vienna Motor Symposium – one of the world’s most important congresses on the automotive technology of today and the future, (and something I'm quite upset I won't be attending this year).
Dr Frank Welsch, member of the board of management for Volkswagen passenger cars with responsibility for technical development sums it up best, saying: “Electrifying conventional drives will enable us to further reduce consumption and emissions while also increasing dynamics and convenience.
“We are starting this extensive electrification campaign with Volkswagen’s best-selling vehicle to date – the Golf. Our newly developed, cost-effective 48V mild hybrid will pave the way for introducing this type of technology to the mainstream”.
Volkswagen will combine the combustion engine with a 48V belt-integrated starter generator and a 48V battery. The 48V mild hybrid makes it possible to “coast” with the combustion engine completely switched off, thereby saving up to 0.3 litres of fuel over 100 kilometres. Moreover, this mild-hybrid solution offers much improved dynamics and convenience as a result of providing an electric boost - which some will welcome.
While 48V technology isn't entirely new - Audi and Bentley have used the technology in their SUVs - it does represent a new chapter in engine design, enabling drives to be electrified in a cost-efficient manner. Fully hybrid powertrains, like those used in the Prius are expensive.
The 48V system will be used in vehicles in addition to the 12V system. In the case of very small wire cross-sections and a lightweight wiring harness, the 48V system enables a considerably higher amount of energy to be saved, for example via recuperation when the vehicle brakes.
The higher voltage also enables a number of operations, including the actuation of the 48V belt-integrated starter generator. On the one hand the starter-generator performs the role of alternator and starter, but at the same time, it functions as a small, lightweight electric motor that immediately increases drive torque by an electric boost. The generator also starts the combustion engine – which is switched off as much as possible while the vehicle is moving.
Another versatile element of the 48V system is its lithium-ion battery. The battery is supplied with energy during a number of operations, including recuperation – i.e. when the vehicle slows down. The starter generator receives the necessary voltage via the battery and the 12V power supply receives the required voltage via the DC/DC converter.
“The basic interaction of different energy sources – electricity, petrol, diesel and natural gas – represents a paradigm shift at Volkswagen. For the first time, the company will simultaneously offer product lines such as the Golf with conventional, electrically assisted drives as well as product lines such as the I.D. with purely electrical drives in the future," says Welsch.
This will result in the product lines diverging into two branches. This new product strategy will come into play for the first time from 2019 onwards with the launch of the next-generation Golf and the first I.D. – two compact Volkswagen vehicles with completely separate technical concepts as well as clearly different design make-ups.
And with these two product lines, Volkswagen is seizing the opportunity to continue to improve efficiency while also helping erase the memory of its diesel past.