This article highlights the need to reduce carbon dioxide emissions by reducing energy consumption. Of course, this can be achieved in various ways, but inter alia, through the practical implementation of the assumptions contained in the CSR programs of individual companies, which include a component on environmental protection and counteracting global warming. The authors also describe a proposal to reduce CO2 emissions by using coke oven gas (if necessary) in exchange for natural gas. Currently, the largest sources of carbon dioxide emissions are the combustion of fossil fuels in power plants, transport—cars and planes, processes related to the production of industrial goods, and deforestation. In the preparation of the article, the analysis of the literature on the subject, analysis of documents, desk research, and two case studies were used. The main goal of the article is to present the possibilities of reducing CO2 emissions by implementing the assumptions of the CSR policy on the example of a selected company (models of such activities are also given). Therefore, the aim of the article is to present selected activities that can contribute to the reduction of carbon dioxide emissions in enterprises; of course, this is specific each time and should be individually selected for each enterprise depending on financial, environmental, and any other conditions. This means that almost all enterprises, organizations, and all other institutions should be obliged to implement an individual environmental policy related to the possibility of reducing carbon dioxide emissions worldwide, and the effects of implementing the assumptions of this policy should be regularly, at least once a year, presented in the CSR reports of a given organization. However, each organization should provide its own examples of how it reduces carbon dioxide emissions. For this reason, this article presents an example of the Marcel CHP plant, which, due to its capabilities, also uses coke oven gas, the use of which results in lower emissions of carbon dioxide than natural gas. Additionally, the article presents a comparative analysis of the use of coke oven gas instead of natural gas. The obtained results show the significant and real possibilities of reducing carbon dioxide emissions.

11# Summary. Internal combustion engines are fuelled mostly with liquid fuels (gasoline, diesel). Nowadays the gaseous fuels are applied as driving fuel of combustion engines. In case of spark ignition engines the liquid fuel (petrol) can be totally replaced by the gas fuels. This possibility in case of compression engines is essentially restricted through the higher self-ignition temperatures of the combustible gases in comparison to classical diesel oil. Solution if this problem can be achieved by using of the dual fuel system, where for ignition of the prepared fuel gas -air mixture a specified amount of the liquid fuel (diesel oil) should be additionally injected into the combustion chamber. For assurance that the combustion process proceeds without mistakes and completely, some basic conditions should be satisfied. In the frame of this work, three main aspects of this problem are taken into account: a. filling efficiency of the engine, b. stoichiometry of the combustion, c. performance of mechanical parameters (torque, power). A complex analysis of these conditions has been done and some achieved important results are presented in the paper.

The theoretical analysis of the charge exchange process in a spark ignition engine has been presented. This process has significant impact on the effectiveness of engine operation because it is related to the necessity of overcoming the flow resistance, followed by the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by the throttling valve is especially high during the part load operation. The open Atkinson-Miller cycle has been assumed as a model of processes taking place in the engine. Using fully variable inlet valve timing the A-M cycle can be realized according to two systems: system with late inlet valve closing and system with early inlet valve closing. The systems have been analysed individually and comparatively with the open Seiliger-Sabathe cycle which is a theoretical cycle for the classical throttle governing of the engine load. Benefits resulting from application of the systems with independent inlet valve control have been assessed on the basis of the selected parameters: fuel dose, cycle work, charge exchange work and a cycle efficiency. The use of the analysed systems to governing of the SI engine load will enable to eliminate a throttling valve from the system inlet and reduce the charge exchange work, especially within the range of part load operation.

In this paper the calculations algorithm of heat-transfer coefficient in the combustion chamber of the internal combustion engine is presented. Developed algorithm is based on the in cylinder pressure data. The proposed algorithm can be helpful to determine the average values of heat-transfer coefficient from working medium to the combustion chamber walls (crown of a cylinder head, cylinder walls and piston head) during combustion process. The calculation method includes modified one zone heat release model in combustion chamber of SI engine. Proposed method consists in closing the energy balance equation by the coefficient which expresses the heat losses to the walls of the combustion chamber. The average value of the heat losses during combustion process is calculated by two steps. Firstly, the integration of the energy balance equation (without specifying the heat losses) leads to designation of the so-called net value of heat released in cylinder. In the next step the amount of the total energy supplied to the cylinder is determined taking into account the chemical energy of the supplied fuel. The difference between the supplied value of chemical energy and heat released net value allows to determine the heat losses average value. In last stage, the heat flow equation leads to calculate the mean value of heat transfer coefficient during combustion process.

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