48 V Diesel hybrid: a strong combination for improved real-world fuel economy and driving performance?

Abstract

In November 2017 the European Commission proposed the final CO₂ fleet targets until 2030. Conventional combustion technology alone will not be sufficient to achieve these very ambitious targets due to thermodynamic limitations. Hence a broad introduction of electrification in powertrain technology is required to avoid penalties for missing the fleet targets.

Based on those legislative boundaries, different studies predict the broad introduction of 48V powertrains in Europe as cost effective mass market solution. Main reason for this trend is seen in the variability of the 48V hybrid components which should enable a broad variety of hybrid configurations also for existing powertrain structures. But beside the legislative boundaries the main driver for the success of a powertrain technology depends on customer’s acceptance. Due to the political and social debate following the “Diesel Scandal” customer’s trust in cycle based test results is limited which leads to the necessity to prove todays and future powertrain technologies under real driving conditions.

Based on this context Honda R&D Europe built-up a demonstrator vehicle to evaluate the benefits and limitations of the 48V mild hybrid technology in real driving situations. Base vehicle was a C-segment SUV with a very efficient 1.6l diesel engine. The vehicle has been equipped with a belt starter generator system as well as an electric supercharger. An overall power increase was realized by application of a bigger turbocharger. The final evaluation of the system has been done targeting significant CO₂ reduction and improving the driving performance at the same time. The final results of these measurements will be presented in this paper answering the initial question if the 48V technology is “a strong combination for improved real world fuel economy and driving performance”.