Effect of Key Operating Parameters on Homogenous Reactivity-Controlled Compression Ignition Concept with Renewable Fuels

<div>As part of the dTEC MORE project, sustainable powertrain technologies are being explored, including an alternative combustion concept tailored for engines in serial hybrid powertrains. Among the low-temperature combustion strategies, Reactivity-Controlled Compression Ignition (RCCI) is a prominent approach, offering significant reductions in NOx and soot emissions while enhancing combustion efficiency.</div> <div>The dual-fuel nature of RCCI enables improved control over combustion by utilizing fuels of differing reactivities. In this study, a premixed RCCI strategy was implemented using ethanol as a port-injected low-reactivity fuel and octanol as a directly injected high-reactivity fuel. The experimental work was conducted on a single-cylinder research engine with design features that are found in a gasoline passenger car application.</div> <div>Key combustion parameters such as the start of injection (SOI) of the high-reactivity fuel, injection pressure, intake temperature, lambda, premixed fuel ratio, and valve overlap were varied and evaluated on the engine test bench. The impact of these parameters on performance, combustion stability, and emissions was systematically analyzed.</div> <div>The results were benchmarked against a baseline direct-injected gasoline combustion cycle with a higher compression ratio. The comparison highlights the advantages of the premixed RCCI strategy, particularly in reducing NOx and soot emissions. Additionally, the test results also support in the future steps to model and validate the simulation models, to achieve higher efficiency and lower emissions.</div>