The recuperated split-cycle engine as a sustainable heavy-duty solution

The Recuperated Split Cycle Engine (RSCE) is a new type of in-ternal combustion engine (ICE) with potential for clean, sustainable heavy duty, longhaul and distributed generation applications. The RSCE separates cold (induction, compression) and hot (combustion, expansion) parts of the cycle, and recovers waste exhaust heat between them via a recuperator. The engine has been developed to Proof of Concept stage using a mix of hardware testing and simulation; and has shown exceptional results for both air quality emissions and thermal efficiency. A single-cylinder engine has demonstrated controllable cool combustion, with NOx emissions that can be after-treated to SULEV or below, and potential for “near zero”. This engine also validated a simulation model of a multi-cylinder prototype, demonstrating Brake Thermal Efficiencies of between 50% and 60% depending on the level of technology applied. These credentials place it on a par with “zero emissions” propulsion. A life-cycle analysis is presented for the concept in the mid-term, highlighting its advantage against alternatives with high embedded energy. The concept is compatible with either Diesel or Natural Gas and their sustainable replacements, and potentially with future fuels such as sustainably sourced Hydrogen or Ammonia; further thinking is described on how such fuels may be supplied to the heavy duty sector in the longer term. Because the engine and fuel both have “backward compatibility” with existing products, the transition to sustainable power is far easier than with zero-emission alternatives, delivering substantial GHG mitigation in the 2030 timeframe while providing a long-term solution beyond that.