The paper presents the results of examination of particulate matter emission from the

The study presents results of a research work on two various Diesel engines adapted for dual fuel feeding with CNG gas and diesel oil. The first engine is naturally aspirated, medium-sized engine, corresponding to engines mounted as power units in trucks and buses. Natural gas was used as the main fuel to this engine, and amount of diesel oil was reduced to minimum according to criterion of correct operation of injection system and reliable ignition of gaseous mixture. The second engine was a high-speed, supercharged engine of Fiat 1.3 MJT type, destined to powering of passenger cars. This engine is equipped with modern engine technologies, high-pressure injection system of Common Rail type with division of fuel dose and recirculation of exhaust gases, with catalytic converter and DPF filter. To fueling of this engine was used small additive of gas, aimed at reduction of smokiness of exhaust gases. Performed research has shown beneficial effect of gas on engine efficiency, reduction of concentration of nitrogen oxides, smokiness of exhaust gases and emission of particulate matter. Simultaneously, however, emissions of carbon monoxide and hydrocarbons had increased, especially in area of partial engine loads. Results of the study are pointing at possibility of installation of dual fuel system in traction engines with different size.

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The development of internal combustion engines involves various new solutions, one of which is the use of dual-fuel systems. The diversity of technological solutions being developed determines the efficiency of such systems, as well as the possibility of reducing the emission of carbon dioxide and exhaust components into the atmosphere. An innovative double direct injection system was used as a method for forming a mixture in the combustion chamber. The tests were carried out with the use of gasoline, ethanol, n-heptane, and n-butanol during combustion in a model test engine—the rapid compression machine (RCM). The analyzed combustion process indicators included the cylinder pressure, pressure increase rate, heat release rate, and heat release value. Optical tests of the combustion process made it possible to analyze the flame development in the observed area of the combustion chamber. The conducted research and analyses resulted in the observation that it is possible to control the excess air ratio in the direct vicinity of the spark plug just before ignition. Such possibilities occur as a result of the properties of the injected fuels, which include different amounts of air required for their stoichiometric combustion. The studies of the combustion process have shown that the combustible mixtures consisting of gasoline with another fuel are characterized by greater combustion efficiency than the mixtures composed of only a single fuel type, and that the influence of the type of fuel used is significant for the combustion process and its indicator values.

The article discusses the effect of fuel dose division in the Diesel engine on smoke opacity and composition of the emitted exhaust gas. The