Progress and recent trends in 48 V hybridisation and e-boosting technology on passenger vehicles – a review

Abstract

Electrification of the powertrain system will play an important role in reducing fuel consumption and engine-out emissions in the next few decades. Compared to the pure electric and full hybrid concept, 48 V mild hybridisation and the accompanying 48 V e-boosting concept, due to their superior cost-benefit performance, may become mainstream for the next generation of fuel reduction measures. The mild hybrid system can realise advanced stop-start, active and passive engine-off coasting, braking recuperation, boost assistance, e-creeping and torque vectoring functions, and is thus deemed to give approximately 10-15% fuel consumption benefits in the New European Driving Cycle (NEDC); and the e-boosting concept, due to its capability for further downsizing and down-speeding, allows the engine operating points to be shifted into a more efficient area. A strong synergy between 48 V mild hybridisation and the 48 V e-boosting concept has been found after reviewing both technologies, and the trends for developing such a combined electrical system are also discussed. Together with more engine and vehicle component electrification, fuel efficiency could be further improved, although the interactions between these technologies are highly complex and need to be optimised at a system level.

Modelling and Control of a Hybrid Urban Bus

“…However, despite being built upon an existing vehicle topology, the development of the configuration is not without its challenges. Firstly, the power demands in the commercial sector are significantly higher than those encountered in the wider automotive sector, in which 48V architecture has become popular for many of the emerging mild-hybrid and hybrid configurations [6]. There are several configurations, categorised by the location of the MGU in the powertrain, that can be adopted, ranging from P0 which incorporates a belt driven starter and generator through to P4 with the MGU located on the drive axle.…”

“…There are several configurations, categorised by the location of the MGU in the powertrain, that can be adopted, ranging from P0 which incorporates a belt driven starter and generator through to P4 with the MGU located on the drive axle. During development of the current vehicle architecture, an initial P0/P1 style hybrid with an engine mounted MGU on a 48V system was considered, as this is the most straightforward configuration to implement and is one of the most popular configurations for emerging vehicles [6]. However, for this particular powertrain, it was found to have limited fuel consumption reduction benefits when balanced against the increased cost of the vehicle with the new electrified components.…”

Fuel economy improvement and emission reduction of 48 V mild hybrid electric vehicles with P0, P1, and P2 architectures with lithium battery cell experimental data

“…7,8 The fuel economy, performance, and cost of hybrid electric vehicles are significantly influenced by the powertrain architectures. Based on the location of the electric machine within the powertrain or driveline, the hybrid powertrains architectures can be categorized into five groups as P0, P1, P2, P3, and P4, 9 as shown in the Figure 1. The P0 architecture is mainly for engine start/stop function (engine idle elimination) while utilizing 12 V Starter-lighting-Ignition (SLI) battery.…”

“…However, a higher torque electric machine is necessary in P3 and P4 architectures to enable pure electric drive since the torque from the electric machine is not amplified by the transmission. 3,7,9,20…”

A Hybrid End-to-End Control Strategy Combining Dueling Deep Q-network and PID for Transient Boost Control of a Diesel Engine with Variable Geometry Turbocharger and Cooled EGR

“…For more than a decade, engine boosting has seen widespread adoption by passenger and heavy goods vehicle powertrains in order to increase the specific power and enable the downsizing megatrend [2]. However, many challenges still remain, as the regulation requirements become stricter, and the demand for low-carbon powertrains increases [3]. Currently, the growing expectations of vehicle performance, including an excellent transient response with high boost levels, have converged within the demand for increased downsizing and higher levels of EGR.…”