The Aero Derivative Reactivity-Controlled Compounded Internal Combustion Engine Cycle: Achieving Near-Carnot Efficiencies for Medium and Heavy-Duty Applications

An aero variant of the Reactivity-Controlled Compounded Internal Combustion Engine (RCCICE) architecture is introduced. Prior work illustrated a new combustion system leveraging the ignition delay properties of sustainable fuels to create an extremely high thermal efficiency engine architecture suitable to compounding. This compounded architecture is able to operate globally stoichiometric with a core piston engine and high levels of compounding enabled by recuperation, allowing use cases such as heavy-duty surface transport to reduce operating costs and comply with tailpipe emissions regulations. However, the dual bottoming with Brayton and Rankine cycles are heavy for aero use cases, and the Rankine has slow transients making it more useful for stationary power generation or loads that are able to tolerate the inability to reduce power to zero quickly. The new aero variant increases the recuperation and Brayton subsystem power levels and eliminates the Rankine subsystem for much greater power to weight with improved cruise thermal efficiency but reduced efficiency at peak. This solution increases peak power by 68% to 1,750kW shaft power at a thermal efficiency dropping from 67% to 56%, but improving power to weight from 4.8:1 to 10.2:1 kW/kg.