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Among the new low temperature combustion modes, Reactivity-Controlled Compression Ignition (RCCI) offers a low NOx-soot trade off (keeping a relatively high engine efficiency). Also, RCCI permits the introduction of a renewable fuel with a lower CO2 direct emission such as short-chains alcohols. For this work, methanol and diesel fuel were used as low and high reactivity fuels, respectively. A 1.3 L single-cylinder engine, with a cylinder volume usual in medium- and heavy-duty truck and bus engines, was used in this work. The engine was operated at an engine speed of 1600 rpm and 25% load (representing one of the 13-mode test on medium duty trucks), which results in an indicated mean effective pressure of 5.2 bar. The effects of methanol substitution ratio (MSR) at 20 and 35% on performance and pollutant emissions was investigated and compared to conventional diesel combustion (CDC).

Regulated gaseous emissions and particle concentrations, with commercial diesel fuel, animal fat biodiesel and gas to liquid (GTL) fuel from a Low Temperature Fischer-Tropsch process, have been studied. Tests were carried out in a light duty vehicle (Nissan Qashqai, 110 kW, Euro 4) equipped with variable geometry turbocharger (VGT), cooled exhaust gas recirculation (EGR), common rail with split fuel injection strategy, diesel oxidation catalyst (DOC) and diesel particle filter (DPF). Vehicle tests were carried out at real-world driving conditions. Specific emissions, in g/km, were determined separately for two test circuits (urban and extraurban). Results show that the use of alternative fuels reduced THC and CO emissions compared to diesel fuel while only slight differences were observed in NOx emissions and in particle number concentration.