Mild-hybrid vehicles: a near term technology trend for CO2 emission reduction

This paper provides a comprehensive overview of mild-hybrid technology and recent developments in 48V mild hybridization of conventional vehicle powertrains. It estimates the CO2 reduction potential, as well as current and future system cost, for different mild-hybrid electric vehicle (MHEV) system configurations. It also reviews the market penetration trends and future projections of MHEV technology in Europe.

For mild-hybrid systems with comparable technical parameters, conservative estimates for the CO2 reduction potential under type-approval conditions compared with a baseline stop/start system range from about 7% for the P0 architecture to almost 16% for the more complex P2, P3, and P4+P0 architectures. Optimizing engine operation and increasing electric motor power can yield an additional 5% to 10% CO2 reduction on P2, P3, and P4 architectures.

The costs of mild-hybrid technologies increase with system complexity. The P0 manufacturing cost is conservatively projected to drop from €558 in 2020 to €338 in 2030. For systems with similar battery capacity and power, the cost for a mild-hybrid technology packet with P2 or P3 architecture is about 30% higher and a P4+P0 system added to a front-wheel drive vehicle is about 50% higher than for the P0 system.