Industry embraces 48V supply in the cause of bringing down emissions

November 27, 2014 // By Christoph Hammerschmidt
At the recent 48V Hybrid electric vehicle conference in Düsseldorf (Germany), two areas of broad agreement emerged; 48V supply is essential to reach the next CO2 and NOx reduction targets in a cost-effective way - and a global standard to establish this technology would be at least helpful.

Keynote speaker Florian Kühnlenz, responsible for series development of low voltage energy systems at Volkswagen AG, set the scene with a presentation of the electric and electronic architecture requirements of dual voltage power supplies in vehicles at 12 and 48V; with initial steps already having been taken for the adoption of the proposed LV148 standard suggested by Audi, BMW, Daimler, Porsche and Volkswagen.

Kühnlenz' outlook is that the introduction of a second voltage at 48V addresses new challenges for automotive electrical and electronic systems, but that most issues have now been identified with preliminary solutions already developed for introduction during the ramp-up to the 95g/km CO 2 requirement by 2020. The displacement of high wattage loads to a more efficient 48V network is expected to be the next step in the development of a new generation of low voltage mild hybrid vehicles.

“Other global carmakers will have to decide whether they want to embrace 48V,” says Paul Bloore, product validation manager for the hybrid product group of Controlled Power Technologies (CPT), a British technology company and a strong proponent of the 48V system. Commenting on the need expressed by tier one suppliers for an international standard when introducing low voltage hybrids and their note of caution should this not happen, he added that “it makes sense to have a common global standard, because 48V hybrids are currently the most cost-effective way of meeting stringent CO 2 emissions being introduced in 2020, compounded potentially by a shift from the current NEDC test to the more aggressive WLTP test, with further 25% reductions anticipated in 2025 and 2030.". According to Bloore, a consensus of global forecasts suggests that 48V hybrids will soon come to dominate the market. "A common international 48V standard would be a smart move," he said.

Salah Benhassine, a specialist in electromagnetic compatibility (EMC) at PSA Peugeot Citroën set out the French carmaker's approach to 48V mild hybridisation by