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<div>Internal combustion (IC) engines play an important role in the global economy by powering various transport applications. However, it is a leading cause of urban air pollution; therefore, new combustion strategies are being developed to control emissions. One promising advanced low-temperature combustion (LTC) technology is gasoline compression ignition (GCI). This experimental study assesses the performance of a two-cylinder engine, emissions, and exhaust particulate characteristics using G80 (80% v/v gasoline and 20% v/v diesel) blend operating in GCI mode vis-à-vis baseline conventional diesel combustion (CDC) mode using diesel. The effects of double pilot injection, Pilot-1 proportion (10–30%), and main injection timing were investigated on the GCI combustion. Experiments were performed at different engine loads (3, 4, and 5 bar brake mean effective pressure [BMEP]) at a constant engine speed (2000 rpm). GCI combustion showed higher brake thermal efficiency (BTE) than CDC mode at medium loads. Hydrocarbon (HC) and carbon monoxide (CO) emissions increased in GCI mode, but oxides of nitrogen (NOx) were reduced than the baseline CDC mode. High pilot ratio and late main injection timing tests showed higher HC and CO emissions in the GCI mode at low engine loads. The GCI mode engine emitted higher nucleation mode particles and nanoparticles than baseline CDC mode at high engine loads. Using a triple injection strategy, GCI engines simultaneously reduced NOx and particulate matter (PM) emissions, especially at high loads. Controlling these emissions in baseline CDC mode engines is otherwise quite challenging.</div>

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<div>Climate change and stringent emission regulations have become major challenges for the automotive sector, prompting researchers to investigate advanced combustion technologies. Gasoline compression ignition (GCI) technology has emerged as a potential solution, delivering higher brake thermal efficiency with ultra-low nitrogen oxides (NOx) and particulate emissions. Combustion stability and controls are some of the significant challenges associated with GCI. This study investigates the combustion characteristics of a two-cylinder diesel engine in GCI mode. GCI experiments were performed using a low-octane fuel prepared by blending 80% (v/v) gasoline and 20% (v/v) diesel (G80). Baseline experiments were conducted in conventional diesel combustion (CDC) mode. These experiments investigated the effects of double pilot injection, first pilot fuel ratio, and the start of main fuel injection timing (10–8°CA before top dead center, bTDC). The results indicated that the GCI mode produced significantly lower (~10%) in-cylinder pressure than the CDC mode. Higher pilot fuel proportions exhibited a lower heat release rate (HRR) at low loads. Retarded main injection showed a lower heat release in the premixed combustion phase than the advanced main injection case at all loads. In addition, retarded main injection timing showed retarded start of combustion (SoC) and end of combustion (EoC). GCI mode exhibited higher cyclic variations than baseline CDC mode, which need to be addressed.</div>