The current study examines the combined effects of injection strategy, injector
configuration, and fuel blending on the combustion performance and emission
behavior of a light-duty compression-ignition (CI) engine operated in premixed
charge compression-ignition (PCCI) combustion mode. Experiments were conducted
in PCCI combustion mode using a diesel–gasoline blend (D80G20, 80% diesel and
20% gasoline by volume). A modified injector configuration, with a
split-injection scheme comprising pilot and main injection events, was
implemented to enhance mixture preparation and control combustion
characteristics. The baseline configuration utilized PCCI mode with diesel
(D100) and an inclined injector orientation. The results indicate that blending
gasoline into diesel prolongs ignition delay and facilitates charge premixing,
hence improving the stability of the PCCI combustion regime. Using a vertically
oriented injector with a symmetric spray pattern significantly improves air–fuel
mixing, and split-pulse injection enables more accurate control of combustion
phasing. Among the tested strategies, the D80G20 blend, combined with a vertical
injector and optimized split injection, achieved the highest brake thermal
efficiency at 60% load, improving by 10.1% over the baseline case. In addition,
unburned hydrocarbon (HC) and carbon monoxide (CO) emissions were significantly
reduced by 54.1% and 49.4%, respectively. Additionally, the load extension was
increased to 77%, which is limited to 60% of the engine-rated load in PCCI with
diesel fuel. The current integrated approach provides a viable pathway to
implement the PCCI mode to improve engine thermal efficiency and reduce
pollutant emissions without significant hardware modifications, thereby
supporting the transition to cleaner combustion technologies.
