48 V Mild Hybrids Dominate
48 V Mild Hybrids Dominate

The consensus of global forecasts suggests that 48 V mild hybrids will soon come to dominate the market.

In fact, due to tightening vehicle efficiency and emissions regulations and increasing demand for onboard electrical power, higher voltages, in the form of supplemental 48 V subsystems, may soon be nearing production.

That’s what Kevin Jost, long-time editor of Automotive Engineering and currently, SAE International’s ground vehicle content strategist, proposes in a new book titled, “48-Volt Developments.”

With development experiencing fits and starts over the past few decades, the concept of higher-voltage electrical systems in vehicles (which has evolved from 12 V conventional systems to include 200 V and 600 V full hybrids and electric vehicles) is not new…

But, there are many improvements and benefits that are making it popular again:

  • In addition to improved fuel economy and reduced emissions, 48 V systems could potentially save costs on new electrical features and help better address the emerging needs of future drivers
  • The new technology is “extremely economical because it can be easily integrated into an existing vehicle architecture, and the small 48-volt battery means battery costs are reasonable,” said Christopher Breitsameter, Head of Business Development and Strategy, Continental Powertrain Division
  • Electric turbo and supercharging could benefit from 48 V networks. Hyundai and Kia are said to be developing a mild-hybrid diesel powertrain using an electric supercharger in conjunction with a 48 V network. According to Paul Bloore, Product Validation Manager for Controlled Power Technology’s hybrid product group, electric boosting using energy recuperated, rather than lost in friction from the brakes, not only reduces CO2 and NOx emissions, but can also have a positive impact on vehicle performance and drivability
  • Compared with 200-600 V full hybrid and battery electric vehicles, the lower-voltage approach avoids the need for high-cost safety features and large battery packs. CPT estimates that if 48 V technology and related emissions-reduction strategies could be universally applied to the more than 100 million vehicles forecast to be produced per year from 2020—98% of them with gasoline and diesel engines—annual CO2 emissions could be reduced by 100 million t (110 million ton) globally per year

Of course, challenges to 48 V system implementation still exist, like the need for an international 48 V standard.  Per Bloore, having a common global standard makes sense because 48 V hybrids are currently the most cost-effective way of meeting stringent CO2 emissions in the buildup to 2020 European regulations. This is compounded, potentially, by a shift from the current NEDC to the more aggressive WLTP test, with further 25% reductions anticipated in 2025 and 2030.