Examining the Effect of Triboelectric Phenomena on Wear-friction Properties of Metal-polymeric Frictional Couples

The influence of triboelectric phenomena on the wear-friction properties of microasperities contacts of friction couples of drum – shoe brakes was explored. As a result of the conducted research into the wear-friction properties of metal-polymeric frictional couples of braking devices under laboratory and operational conditions at the nano-, micro- and millilevel during triboelectric interaction, the regularities of changes were established:– of magnitudes of the contact difference of potentials of frictional couples "grey cast iron – polymers" of the drum-shoe brake on the surface temperature of linings and specific loads;– of circulating thermal and tribocurrents on the time of friction interaction of frictional couples "cast iron – polymers" and "steel – polymers" at different sliding velocities;– of generated tribocurrents in the contact of two-layered structures "steel – polymer" and circulating tribocurrents through the three-layered structure "steel – polymer – steel" on the surface temperatures

Research Into Emissions of Nitrogen Oxides When Converting the Diesel Engines to Alternative Fuels

We conducted theoretical and experimental research into emissions of nitrogen oxides in exhaust gases of the diesel engines, re-equipped for gas.The research is important because the emissions of nitrogen oxides in the exhaust gases are one of the biggest environmental problems at the present stage of development of designs for internal combustion engines. Therefore, reducing the emissions of nitrogen oxides in diesel engines by re-equipping them to gas fuel is an important task for specialists in design and operation of internal combustion engines.The result of theoretical research is the mathematical model that we constructed in order to calculate emissions of nitrogen oxides in the exhaust gases of diesel engines and the engines, converted to gas fuel. Based on experimental research, we have established dependences of emissions of nitrogen oxides in exhaust gases of the diesel engines, re-equipped for gas, on loading and the crankshaft rotation frequency. Studies have shown that diesel engines, which are converted to alternative gas fuel, reduce emissions of nitrogen oxides in the exhaust gases in a range from 13.9 % to 47.1 % depending on engine rotation and load. The results obtained make it possible to reduce the emissions of harmful substances in exhaust gases of automobile engines and optimize design of the systems for exhaust gases recirculatio