The consortium aims to demonstrate the advanced 48V mild hybrid powertrain architecture, capable of delivering near full hybrid-scale diesel fuel efficiency and reduced CO₂ emissions, through a highly cost-effective package, without compromising increasingly stringent European exhaust emission regulations, which currently require cars to meet Euro 6b air quality standards in terms of NO_x, PM and CO.

In addition, the integration of hybrid and emissions control systems has the potential to deliver up to a 10-12% reduction in fuel consumption, equivalent to sub-80g/km of CO₂ emissions (NEDC). The technology can be delivered at lower costs than a more traditional approach of optimizing each system separately.

Initial analysis shows that costs (based on Ricardo’s estimation) of less than €80 (US$89) per gram of CO₂ reduction for every kilometer traveled is feasible through ADEPT technology. Ricardo believes the above package is very competitive with other fuel economy solutions such as full hybridization.

The concept of “intelligent electrification” enables highly aggressive engine downsizing and down-speeding beyond what might normally be possible other than through more expensive hybridization approaches. This is achieved through the use of torque assist from electrically harvested energy, temporarily stored in a 48V advanced lead-carbon battery with a high rate partial state-of-charge capability similar to a supercapacitor, in combination with 48V electrified ancillaries.

With sophisticated electronic control of the powertrain systems, torque assist can be used to ensure that performance is maintained—or improved upon— throughout the duty cycle while also reducing fuel consumption. By basing the system on 48V electrical architecture, the ADEPT project aims to achieve a highly optimal cost and performance trade-off, including ultra-low emissions, while also delivering significant fuel savings.

ADEPT powertrain architecture. The baseline vehicle for the ADEPT research and development programme is based on an already downsized and competitively fuel-efficient diesel Ford Focus ECOnetic 1.5TDCi, homologated with carbon dioxide emissions of 88g/km.

Key features of the vehicle systems include CPT’s water-cooled SpeedStart switched reluctance belt starter generator (BSG), capable of delivering in excess of 12kW of regenerative braking, as well as near instantaneous and near continuous torque assist levels of over 7kW— sufficient to enable significant engine down-speeding in addition to a highly capable start-stop functionality.

Further energy recovery is achieved from CPT’s exhaust-mounted 48V turbine integrated exhaust gas energy recovery system known as TIGERS. Rated at 2.4kW, TIGERS is capable of providing further power recuperated from the exhaust downstream of the turbocharger. The exhaust gas is diverted to the TIGERS unit via two bespoke emissions control valves developed by Faurecia Emissions Controls technologies for the ADEPT project.

The recovered energy is stored in the advanced lead-carbon battery pack, providing a high power, high endurance, easily recyclable, lithium-free energy storage solution at a competitive cost.

The ADEPT powertrain includes a range of electrical ancillaries powered from the 48V system rather than directly from the engine, including for example, the vehicle air conditioning compressor. In addition to powering these ancillaries and facilitating a significantly improved start-stop functionality, ADEPT’s 48V architecture also provides significant levels of torque assist from the BSG to offset fuelling to the engine for improved fuel economy, and to increase overall powertrain torque capability for enhanced vehicle performance.

The control strategies deployed have been developed based on extensive vehicle systems simulation work. This has enabled the core powertrain and aftertreatment system, as well as the 48V BSG, ancillaries, battery pack and exhaust energy recovery system, to be operated in a seamless manner, while also providing a valuable computer-aided engineering (CAE) capability to explore further potential avenues of development and optimization opened up through intelligent 48V electrification.

Development completed, testing ongoing. Following the announcement of the ADEPT project in September 2013, initial integration and development tests were carried out by the ADEPT team on an early functional integration prototype, which was revealed at the LCV2014 show. This enabled the project to carry out de-risking of components and systems, and also provided a platform for evaluating control concepts.

The final ADEPT demonstrator vehicle, which has now been completed, provides the fullest implementation of systems to be carried out by the team. At the LCV2016 show, the final results of ongoing vehicle road and laboratory tests will be revealed for the first time. The project partners also intend to make the vehicle available for ride and drive demonstrations at LCV2016.

The ADEPT research project is jointly funded by the UK Government’s Office for Low Emission Vehicles (OLEV) implemented through the UK innovation agency, Innovate UK, with matching contributions from the participating partners.