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Sirvi Autor "Smigins, R." järgi

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  • Pisipilt
    Kirje
    An assessment of stratification of exhaust gases from gasoline and diesel engine
    (2018) Birkavs, A.; Smigins, R.
    Research the aim of which was to find out stratification of main exhaust components outside the tailpipe of the vehicle was realized in Alternative Fuels Research Laboratory of Latvia University of Agriculture using two commercially produced testing vehicl es (diesel and gasoline) and exhaust gas analytical system AVL SESAM FTIR. Additionally there was created a gas testing camera allowing to measure concentration of exhaust gas components in different heights and windless conditions. Regulated and unregulat ed emissions from gasoline and diesel engines were measured and discussed. Results obtained during the measurements showed main stratification of toxic components from both engine types from 0.6 to 1.1 m from the ground making a risk to get some health pr oblems by inhalation, especially for children. Main components (NOx, CO, HC) of exhaust gases of gasoline engines stay in the air for about 15 minutes in height of 1.0 m from the ground level, while methane and acetylene stay in the air for a 15 minutes in height of 0.6 m from the ground level.
  • Pisipilt
    Kirje
    Experimental research on compatibility of mineral and biobased hydraulic oils
    (2018) Birkavs, A.; Smigins, R.
    The use of biobased hydraulic oils becomes more popular in the different industries, but especially in agriculture machinery. This is stimulated by the fact that significant amount of hydraulic oils effluence in the environment and therefore leaves a negative impact to the e cosystem. Besides of that, the part of sold hydraulic oils grows and now forms approximately 15% of total oil consumption amounts worldwide (Nagendramma & Kaul, 2012) . The aim of this research was to study the compatibility of the comercially produced mine ral and biobased hydraulic oils, identify viscosity of a different mixtures in the entire work temperature range, as also changes of anti - frictional properties. Two different oils and three mixtures were tested. Special hydraulic experimental apparatus was established for visual observation of fluid properties. Sliding friction bench was used for the comparision of friction properties. The results showed that change of the working pressure and temperature of the hydraulic oil in the various mixtures of mine ral and biological hydraulic oils do not change its original appearance. It was observed that the highest viscosity 71 mm 2 s - 1 and worst anti - friction properties is for the 50% mix of mineral and biologial hydraulic oil at 20 °C ambient temperature.
  • Pisipilt
    Kirje
    Performance and emissions of an agricultural diesel engine with hydrogen injection under different load modes
    (Estonian University of Life Sciences, 2025) Smigins, R.; Amatnieks, K.; Birkavs, A.; Kryshtopa, S.
    Excessive use of fossil fuels in transport sector in the last decades stimulated rise in global energy consumption in such way leaving harmful effects on human health and environment. The scale of decarbonization of transport sector in the next decade could be challenging for European Union (EU) as demand for renewable energy, like wind, solar and hydro, will definitely rise. The aim of this study is to find whether hydrogen could be optimal solution for emission reduction in agricultural machinery. In this regard, research was carried out with KOHLER KDI 1903 M diesel engine looking on main performance parameters, as also regulated emissions operating engine with conventional diesel fuel and different hydrogen injection volumes under different loads. Fuel consumption was measured with AVL KMA Mobile device, while emissions was determined using AVL SESAM FTIR exhaust gas analytical system. During the tests, it was observed that the addition of a higher hydrogen concentration provides more substantial benefits that includes a larger impact on fuel consumption and carbon dioxide (CO2) emissions. Other emissions such as carbon monoxide (CO) emissions had smaller but positive impact, while the addition of hydrogen gas had various impact on nitrogen oxide (NOx) emissions. At the same time decrease in particulate matter (PM) emissions was observed with higher hydrogen concentrations and more substantial impact was observed during higher load conditions and higher hydrogen concentration.