Przemysław Borowski

Combustion process shaping by use of different strategies of multiple fuel injection in a CI model engine

Technological advancement in combustion systems of diesel engines triggers the need of fulfilling many contradictory requirements. Among those are such issues as maintenance of environmental standards in terms of the exhaust emissions with a simultaneous preservation of the thermodynamic properties of the combustion process and fuel consumption. The paper discusses the results of research on the influence of the strategies of fuel dose division on the combustion process and operational indexes in a model engine. The paper also contains an exhaust gas analysis conducted with the use of a rapid compression machine. The investigations of the combustion process (development of the self-ignition spots) were conducted using high speed camera. The recorded images related to the period from the onset of the injection to the beginning of the appearance of combustion spots have also been analyzed. The following have been varied: number of doses, size of doses, dwell times and excess air coefficient. The authors performed a comparative analysis of the thermodynamic indexes of the combustion process obtained from the indicator tracings. The achieved results show possibilities of the influencing on the combustion process course and emission of exhaust toxic compounds by application of multiple injection and its properly selected strategy containing proportions in fuel doses and dwell times between them.

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

AbstractThe 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.

Investigations into High-Pressure Diesel Spray-Wall Interaction on Reduction of Exhaust Emission from DI Diesel Engine

The current paper is a continuation of research on fuel atomization presented in SAE 2012-01-1662. The influence of varied position of the injector inside the combustion chamber on combustion, toxic compounds formation and exhaust emission were investigated. The simulation research (injection and combustion with NO formation) was supported with the model using the FIRE 2010 software by AVL. Modelling studies of toxic compounds formation were compared with the results of measurements on single-cylinder AVL 5804 engine. There thermodynamic evaluation indicators and exhaust emission were made.

Analysis of a dual-fuel combustion engine fueled with diesel fuel and CNG in transient operating conditions

The paper presents the thermodynamic analysis of the engine supplied with small and large diesel fuel doses while increasing natural gas quantity. The paper presents changes in the combustion process thermodynamic indexes and changes in the exhaust gas emissions for dynamically increased share of the gaseous fuel. The cylinder pressure history was subject to thermodynamic analysis, . based on which the mean indicated pressure, the heat release rate, the quantity of heat released as well as the pressure rate increase after self-ignition were determined. These parameters were also referred to the subsequent engine operation cycles by specifying the scope of the change per cycle. The relationship between the engine load and the start, the center and the end of combustion while increasing the gas amount supplied to the cylinder was indicated. The presented analysis of the results indicates significant impact of the changes in the supplied gas amount on the engine operating indexes and exhaust emissions. The conducted tests made it possible to confirm that significant cooling of the cylinder (determined by the constant temperature of exhaust gas) does not allow combustion of a dual-fuel mixture during dynamic change of the engine fueling. It was shown that there is a relation between the thermal history of the cylinder (steady state conditions), the engine fueling rate and the possibility of combustion of a diesel-methane mixture.