A Practical Recuperated Split Cycle Engine for Low Emissions and High Efficiency



14th International Conference on Engines & Vehicles
Authors Abstract
The Recuperated Split Cycle Engine is a new type of ICE, offering a step change in efficiency and tailpipe emissions. It targets the heavy duty, long-haul sector (trucks, off-highway, rail, shipping), where electrification is most challenging, and distributed generation, where capacity is required to support rising electrification. The engine separates cold (induction, compression) and hot (combustion, expansion) parts of the cycle; waste exhaust heat is recovered between them via a recuperator, as in a recuperated gas turbine. Recent research presented at this conference [1] shows that the sonic airflows seen in the induction event give rise to extraordinary fuel mixing and clean, cool combustion, with potential for after-treated emission levels between SULEV and zero-impact (either unmeasurable or below ambient). Recuperation and thermal insulation of the hot cylinder (both feasible within the capability of common materials) also enable high thermal efficiency, with a flatter efficiency map than a conventional ICE. Combining the two attributes, and introducing sustainable fuels, places this readily manufactured, affordable technology on a par with battery-electric and fuel cell propulsion. Results from simulation to optimise the concept are described. A Ricardo WAVE model was built, with validation of key inputs such as valve breathing, heat transfer and burn-rates from relevant experimental research data. The model was used to develop the cycle around three concepts - a basic layout, “ThermoPower”, was shown to be capable of over 10% fuel saving; “Wet ThermoPower” uses water injection as a compression coolant for greater efficiency, while the ultimate “CryoPower” injects Liquid Nitrogen for quasi-isothermal compression and charge dilution. The optimisation process and practical details are described, especially the development of the critical recuperator, which is subjected to high pressure and temperature; management of its thermal expansion and manufacturing process have been optimised to minimise add-cost over a current ICE bill of materials.
Meta TagsDetails
Owen, N., Treccarichi, F., Atkins, A., Selvaraj, A. et al., "A Practical Recuperated Split Cycle Engine for Low Emissions and High Efficiency," SAE Technical Paper 2019-24-0190, 2019, https://doi.org/10.4271/2019-24-0190.
Additional Details
Sep 9, 2019
Product Code
Content Type
Technical Paper