The VD007 Clean-Sheet V12 Diesel Engine: Bridging the Gap Between Diesel Efficiency and Turbine Power in Aviation

Turboshaft and turboprop engines dominate propulsion for light and medium aircraft due to their high power-to-weight ratios and operational reliability. However, their fuel efficiency at partial load remains limited. Compression ignition engines based on common rail diesel technology offer higher thermal efficiency and lower specific fuel consumption, particularly under off-design operating conditions, motivating their investigation for aviation applications in the 300–4000 shp range. This study presents a comparative benchmarking of conventional piston engines and turboshaft propulsion systems to identify efficiency gaps and scaling challenges for aviation diesel engines. The VD007 project investigates a clean-sheet 60-degree V12 Common Rail Diesel Injection Engine (CRDID) architecture featuring dual injectors per cylinder, short-stroke high-speed operation, and a turbocompound configuration for partial exhaust energy recovery. The research combines literature-based benchmarking, structural analyses, and one-dimensional thermodynamic simulations to evaluate the feasibility of the proposed architecture. Experimental validation of the combustion concept was performed on a four-cylinder prototype tested on a dynamometer bench. The experimental campaign produced torque and power curves together with brake-specific fuel consumption values in the range of approximately 163–225 g/kWh. Analytical scaling and system-level simulations of the full V12 configuration indicate a potential output on the order of 2200 HP. The results highlight both the efficiency potential and the current limitations of high-power diesel architectures in aviation, particularly in terms of power-to-weight ratio and system integration.