Feasible route towards decarbonising marine transport with flexible, hydrogen – enriched, reactivity controlled compression ignition mid-speed engines

Hydrogen (H 2 ) admixing in Reactivity Controlled Compression Ignition (RCCI) technology engines is touted to enhance indicated efficiency (ITE>50%), optimize combustion and reduce greenhouse gas emissions. However, many pending issues remain regarding engine durability, nitrogen oxide (NO X ) emissions and blending limits. These issues are addressed by employing a novel performance-oriented model which simulates under 3 min, combustion physics with similar predictivity (>95% accuracy) as computational fluid dynamic results. This so-called multizone model is parameterized to real-world operating cycles from a dual-fuel mid-speed marine engine. By considering port-fuel injected H 2 , the simulations show that combustion phasing advances at an average rate of 0.3⁰CA/% H 2 , accompanied by a peak reduction in methane slip of 80% achievable at 25% H 2 energy share. Also, engine control oriented issues are addressed by demonstrating either intake temperature or diesel fuel share optimization to negate the drawbacks of combustion harshness and NO X emissions, while improving ITE 1–1.5pp over baseline operation. • Uses real-world operating cycles from a dual-fuel mid-speed RCCI marine engine. • Intake air preheating requirement reduces at the rate of 6.8% with H 2 admixing. • Cylinder-out NO X and hydrocarbon emissions below EU stage V inland waterways limit. • GHG emissions reduces by 31% (tank-to-wake) at 25% H 2 energy share. • Mass-based specific fuel consumption reduces at a rate of 0.6% with H 2 energy share.