Impact of n-butanol-gasoline-hydrogen blends on combustion reactivity, performance and tailpipe emissions using TGDI engine parameters variation

Abstract

Butanol and hydrogen both have unique thermodynamic properties and their combustion reactivity might be significant to energy sustainability. This work examined the effects of n-butanol-hydrogen-gasoline blends on turbocharged gasoline direct injection (TGDI) engine performance, combustion and gaseous emissions at different spark timing (ST), brake mean effective pressure (BMEP) and loads. Experiments are carried out at city transport speed mode under stoichiometric with Air-fuel mixture of 1.0. Results indicate that the brake specific fuel consumption (BSFC) of all blend fractions gradually decreased by 3.79% averagely, which improve the 50% combustion rate and lessen the ignition delay period (IDp) with the increase in rate of heat release (HRR), in-cylinder pressure and injection timing. Moreover, the brake thermal efficiency (BTE) constantly increased as the additives energy ratio increases at all testing modes. With increase in fuel additives, the optimum combustion pressure and HRR rise, and their ignitions come earlier at all modes due to advanced combustion which shortened the IDp as the operating mode was adjusted, and hence, exhibit high maximum pressure rise (MPR) and faster burning speed in the early combustion. When the coefficient of variation in IMEP (COVIMEP) is <5%, both ST and valve are basically suitable, unaffected by ignition timing and moderate SFC and NOx emissions to low condition. Retarding the ignition timing contributes to lower NOx in most cases and HC at 8° CA, and the CO increases by 3.24% on average with an increase in BMEP and load. Finally, effective output work was obtained, as less heat released passing through the cylinder wall is reduced with constant volume of combustion reactivity.