Advantages of the direct injection of both diesel and hydrogen in dual fuel H2ICE

The turbocharged Diesel engine is the most efficient engine now in production for transport applications with full load brake engine thermal efficiencies up to 40-45% and reduced penalties in brake engine thermal efficiencies reducing the load. The secrets of the turbocharged Diesel engine performances are the high compression ratio and the lean bulk combustion mostly diffusion controlled in addition to the better use of the exhaust energy. Despite these advantages and the further complications of hydrogen in terms of abnormal combustion phenomena and displacement effect, the most part of the dual fuel Diesel-hydrogen engines has been developed so far injecting hydrogen in the intake manifold or in the intake port, and then injecting the Diesel fuel in the cylinder to ignite there a homogeneous mixture. This paper shows how a latest production common-rail Diesel engine could be modified replacing the Diesel injector by a double injector as those proposed by Westport since more than two decades for CNG first and then for CNG and hydrogen to provide much better performances. A model is first developed and validated versus extensive high quality dynamometer data for the Diesel engine only covering with almost 200 points the load and speed range. This model replaces the multiple injection strategy with a single equivalent injection for the purposes of the brake efficiency results still providing satisfactory accuracy.