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.
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.
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.
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.
