Nowadays, the road transport system is involved in a “never seen before” evolution, and the automotive diesel engines need to face such critical transition by demonstrating, once again, their potential in contributing to GHG emission reduction. Recent technology trends indicate their potential to reduce the TTW CO2 emission up to 2025 expected targets, which will permit to the mid-size diesel engines to keep playing a significant role during the transition to electrified powertrains. Within the aforementioned picture, the improvement of the base engine technology has still a key role for increasing the overall efficiency, through the reduction of both the friction – by lightening of the mechanics, and of the thermal losses - by a better combustion process management. In this context, the availability of advanced injection systems capable of high injection pressure (>2500 bar) and sophisticated injection pattern (up to ten injection per cycle) have demonstrated to be a fundamental leverage. The present paper describes the results of a cooperative project aimed to identify the best fuel injection system hardware and control strategies in order to reduce tailpipe pollutant and fuel consumption in lighter engines characterized by a low peak-firing-pressure design, while keeping the rated torque and rated power at competitive levels. The project has been performed employing a single-cylinder engine at the state of the art of the technology. The experiments confirmed the needed of an efficient and flexible very-high-pressure injection system to improve fuel consumption and engine-out pollutant emissions while the design peak pressure of the engine is remarkable reduced (up to 40 bar less) to lower the friction losses, without penalties in performance and NVH.