Search Results

In this study, fuel octane number boosters such as toluene, ethanol, methanol, 2-methylfuran (MF), and 2,5-dimethylfuran (DMF) are blended with primary reference fuels (PRFs) in a cooperative fuel research (CFR) engine at research octane number (RON) relevant conditions. In addition to RON determination, engine operation is characterized by measuring (i) cylinder, intake and exhaust pressure, (ii) averaged intake and exhaust temperature, and (iii) air-fuel-ratio. For known fuel blends, the measured RON corresponds well with existing literature. The addition of MF in PRF yields a significant increase in RON and blending octane numbers (indicating booster impact) up to 216. Cylinder pressure fluctuations, the classical definition of knock intensity, are however not consistent, deviating between PRFs and all boosted blends at higher RON values. Moreover, some fuel blends exhibit scarcely any knocking behavior in the test conditions.

Direct injection of natural gas in engines is considered a promising approach toward reducing engine out emissions and fuel consumption. As a consequence, new gas injection strategies have to be developed for easing direct injection of natural gas and its mixing processes with the surrounding air. In this study, the behavior of a hollow cone gas jet generated by a piezoelectric injector was experimentally investigated by means of tracer-based planar laser-induced fluorescence (PLIF). Pressurized acetone-doped nitrogen was injected in a constant pressure and temperature measurement chamber with optical access. The jet was imaged at different timings after start of injection and its time evolution was analyzed as a function of injection pressure and needle lift.

A novel high pressure SCR spray system is investigated both experimentally and numerically. RANS simulations are performed using Star-CD and polyhedral meshing. This is one of the first studies to compare droplet breakup models and AdBlue injection with high injection pressure (Pinj=200 bar). The breakup models compared are the Reitz-Diwakar (RD), the Kelvin-Helmholtz and Rayleigh-Taylor (KHRT), and the Enhanced Taylor Analogy Breakup (ETAB) model. The models are compared with standard model parameters typically used in diesel fuel injection studies to assess their performance without any significant parameter tuning. Experimental evidence from similar systems seems to be scarce on high pressure AdBlue (or water) sprays using plain hole nozzles. Due to this, it is difficult to estimate a realistic droplet size distribution accurately. Thereby, there is potential for new experimental data to be made with high pressure AdBlue or water sprays.