Thermodynamical evaluation of usefulness of future hydrocarbon fuels for use in compression ignition engines

The paper discusses the issues of the influence of the fuel spray formation on the generation of self-ignition spots and the development of pre-flame processes in the cylinder of a model diesel engine. The investigations were carried out for a standard diesel fuel and two other types of fuel that were mixtures of ethanol, butanol, and diethylether in a variety of proportions. By applying optical methods of analysis, the authors determined the geometrical indexes of the injected fuel spray as well as fuel mass distribution in the longitudinal and transverse cross section of the fuel spray during the injection process. The location and number of the self-ignition spots in the combustion chamber were evaluated on the basis of a comparison under various conditions: in presence of the charge swirl and at the lack of it. Research conducted for the single-cylinder engine confirmed the possibility of the use of diesel-like fuels for compression ignition engines.

     

Diagnostics of stratified charge combustion under the conditions of multiple gasoline direct injection

Spark ignition engines fitted in modern vehicles are not such a uniform group in terms of injection and combustion systems as is in the case of diesel engines. The designs of the combustion systems of spark ignition engines are divided into systems of indirect injection into the intake manifold and direct injection into the cylinder. The paper presents an analysis of the results of investigations into the combustion process of charges of different air excess coefficients during a multiple injection of gasoline. The author presented optical investigations and indicator tests realized on a rapid compression machine. The investigations were carried out using a high-speed camera and an engine indicator system. The author indicated the possibilities of diagnostics of the combustion process using both research methods. The distributions of the flame temperature were determined using dual optics enabling a simultaneous recording of the flame image with optical filters. The flame development was presented, and the differences in its velocity were indicated depending on different direct injection strategies.