FEV ECObrid – a 48V mild hybrid concept for passenger car Diesel engines

Powertrain electrification is a key to compliance with future exhaust emission and CO₂ limits. Besides conventional 12 V systems and high-voltage hybrid architectures, 48 V mild hybridization offers significant fuel economy potential and advanced emission control without the need for an entire powertrain redesign. The 48 V power net enables high recuperation capability, improved stop-start functionalities as well as electrical boosting by an electric compressor (e-Compressor) or belt-driven starter generator (BSG).The paper summarizes the key findings of a joint project between FEV and Valeo investigating the potential of mild hybridization and electrical boosting for a downsized passenger car Diesel engine. The considered engine is the well-known FEV HECS concept in its third generation, consisting of a 1.6-liter 4-cylinder engine with single stage VNT turbocharger, e-Compressor, 48 V BSG and dual loop EGR. The engine has been installed in a D-segment vehicle with a dual-voltage electrical system and an advanced model-based engine control unit (ECU) developed by FEV. The paper focuses on the vehicle set-up and performance in transient emission test cycles and under real world driving conditions. In addition, electrical energy management was considered to ensure an efficient power distribution.