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Miscibility of methanol in mineral diesel and stability of methanol–diesel blends are the main obstacles faced in the utilization of methanol in compression ignition engines. In this experimental study, combustion, performance, emissions, and particulate characteristics of a single-cylinder engine fueled with MD10 (10% v/v methanol blended with 90% v/v mineral diesel) and MD15 (15% v/v methanol blended with 85% v/v mineral diesel) are compared with baseline mineral diesel using a fuel additive (1-dodecanol). The results indicated that methanol blending with mineral diesel resulted in superior combustion, performance, and emission characteristics compared with baseline mineral diesel. MD15 emitted lesser number of particulates and NOx emissions compared with MD10 and mineral diesel. This investigation demonstrated that methanol–diesel blends stabilized using suitable additives can resolve several issues of diesel engines, improve their thermal efficiency, and reduce NOx and particulate emissions simultaneously.

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Methanol fueled internal combustion (IC) engines have attracted significant attention due to their contributions in reducing environmental pollution and fossil fuel consumption. In this study, a single-cylinder research engine was operated on MD10 (10% (v/v) methanol blended with mineral diesel) and baseline mineral diesel to explore an optimized fuel injection strategy for efficient combustion and reduced emissions. The experiments were conducted at constant engine speed (1500 rpm) and load (3 kW) using two different fuel injection strategies, namely, single pilot injection (SPI) and double pilot injection (DPI) strategy. For each pilot fuel injection strategy, the start of main injection (SoMI) timing was varied from −3 to 6° crank angle (CA) before top dead center (bTDC). To examine the effect of fuel injection pressure (FIP), experiments were performed at three different FIPs (500, 750, and 1000 bars). Results showed that the MD10 fueled engine resulted in superior combustion compared with baseline mineral diesel, which was further improved by DPI at higher FIPs. The use of DPI strategy was found to be more effective at higher FIPs, resulting in higher brake thermal efficiency (BTE), lower exhaust gas temperature (EGT), and reduced oxides of nitrogen (NOx) emissions compared with SPI strategy. Detailed investigations showed that the addition of methanol in mineral diesel reduced particulates, especially the accumulation mode particles (AMP). Different statistical analysis and qualitative correlations between fuel injection parameters showed that higher FIP and advanced SoMI timings were suitable for particulate reduction from the MD10 fueled engine.

Reactivity controlled compression ignition (RCCI) mode combustion has attracted significant attention because of its superior engine performance and significantly lower emissions of oxides of nitrogen (NOx) and particulate matter (PM) compared with conventional compression ignition (CI) mode combustion engines. In this experimental study, effects of fuel injection pressure (FIP) of high reactivity fuel (HRF) and premixed ratio of low reactivity fuel (LRF) were evaluated on a diesel-methanol fueled RCCI mode combustion engine. Experiments were performed in a single cylinder research engine at a constant engine speed (1500 rpm) and constant engine load (3 bar BMEP) using three different FIPs (500, 750, and 1000 bar) of mineral diesel and four different premixed ratios (rp = 0, 0.25, 0.50, and 0.75) of methanol. Results showed that RCCI mode resulted in more stable combustion compared with baseline CI mode combustion. Increasing FIP resulted in relatively higher knocking, but it reduced with increasing premixed ratio. Relatively higher brake thermal efficiency (BTE) of RCCI mode combustion compared with baseline CI mode combustion is an important finding of this study. BTE increased with increasing FIP of mineral diesel and increasing premixed ratio of methanol. Relatively dominant effect of increasing FIP on BTE at higher premixed ratios of methanol was also an important finding of this study. RCCI mode combustion resulted in higher carbon monoxide (CO) and hydrocarbon (HC) emissions, but lower PM and NOx emissions compared with baseline CI mode combustion. Increasing FIP of HRF at lower premixed ratios reduced the number concentration of particles; however, effect of FIP became less dominant at higher premixed ratios. Relatively higher number emissions of nanoparticles at higher FIPs were observed. Statistical and qualitative correlations exhibited the importance of suitable FIP at different premixed ratios of LRF on emission characteristics of RCCI mode combustion engine.