Abstract
The utilization of coal, an alternative to petroleum, has been expected to expand especially for large-size, low-speed internal combustion engines.
The purpose of this investigation is to clarify the physical properties and spray characteristics of liquefied coal diesel fuel blends, and also to analyze the combustion characteristics, engine performance, and exhaust gas emissions in a small-size, high-speed diesel engine with these blends.
As a result of the present investigation, it was found that the MacCoul equation describes the viscosity-temperature property of the blends, and that their spray is adequately and perhaps better atomized than usual diesel fuel sprays. The recommended blending ratio of liquefied coal fuel is 40v-% or less to achieve smoke reduction with a minimum increase in specific heat consumption, noise, and NOx emissions. Some of the combustion properties of the blends such as ignition lag, smoke, noise and others, can be evaluated qualitatively by the cetane index calculated from the API density and the 50% distillation temperature.
