Combustion chamber diameters, an advance angle of fuel injection, injection rate, minimum ratio of air excess, methods of forcing, and oil cooling affect the heat exchange processes of engines. The method of thermal calculation of the working cycle makes it possible to consider the change in the physical properties of the working fluid, the effect of heat transfer between the working fluid, and the environment during the implementation of the working cycle. The main parameters of the gas at characteristic points of the indicator diagram are determined as a result of performing a thermal calculation, which makes it possible to assess the cycle perfection degree. Some of the main parameters of the working fluid (pressure, temperature) and the nature of their change can serve as input data when calculating engine parts for strength. The amount of mechanical work obtained in the cycle and the value of gas volume at the expansion process end demonstrates not only efficiency, but also the dimensions and weight of the engine, namely, indicators that affect the overall layout of machines.
Energy is essential for the development of human society. Biogas plants, as a part of an integrated product-to-energy system, are an alternative to the use of waste biomass as raw materials due to their energy production capacity and thermal insulation material. Animal waste is an important resource that is used to replenish organic matter and improve soil conditions. Depending on the weight, cattle produce approximately 4 to 6 tons of fresh manure per year. With the constantly increasing prices for fossil energy resources, as well as the depletion of oil and gas reserves, an increasing number of countries are developing alternative energy sources. One of these types is biogas. It is necessary to note that the main disadvantage of biogas energy is the significant weight of specific capital costs and low profitability of projects. Despite this, in Russia there is the increase in demand for biogas units (BGU), both for small consumers (with a digester volume of 3-20 m3) and for medium-sized consumers (with a digester volume of 30-100 m3). The point is that biogas technologies properly fit into the UN Doctrine of sustainable development of society. Many in Russia are committed to this idea. They are guided by the principle “Reason is a clumsy instrument of a scientist; intuition is the unmistakable leader of the seer” and try to solve this problem each in his own way. According to UN experts, this very integrated approach, when a scheme for the selection of enterprises and industries operating on one type of raw material is carried out, and waste and byproducts of one production act as raw materials or semi-finished products for another type, can completely solve the problem of sustainable development of society.
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