Search Results

Although methane number is widely used to predict knocking occurrence and its intensity, it does not determine a fuel composition uniquely, that means, the knocking intensity by the different composition fuel must show difference even if the same methane number fuels are employed. To establish a novel index, the knocking intensity and the autoignitive propagation velocity, as consequence of spontaneous ignition process, are investigated both experimentally and numerically by using the different composition gaseous fuels with same methane number. Methane/ethane/air and methane/n-butane/air mixtures with the same methane number of 70 and the equivalence ratio of 0.5 were employed. They are rapidly compressed and ignited spontaneously by a Rapid Compression Machine. Ignition delay times, autoignitive propagation velocities, and knocking intensity were measured by acquired pressure histories and high-speed imaging.

The influence of ethanol volume fraction on the spontaneous ignition of homogeneous premixed gas reformed by non-equilibrium plasma was investigated. The HCCI experiments of the gas was carried out using a Rapid Compression Machine (RCM). The spontaneous ignition process and reforming process were numerically investigated by reaction simulation in OD. A simplified model was proposed to explain the influence of the reforming of the gas with different ethanol volume fractions, and the model was validated. These results indicate that the influence of the reforming on ignition delay of cool flame is almost irrespective of the ethanol volume fractions.