Annotation: Combustion engines operate over a wide range of power and speed. To the greatest extent, this applies to automotive and tractor engines and diesel engines operating at fractional and idle loads for a significant part of the operating time. When designing engines, the choice of their main design and layout parameters is carried out in a comprehensive manner, taking into account the provision of the required power and efficiency in the modes of maximum torque and rated power. However, ensuring the economical operation of modern highly accelerated diesel engines at low loads and idling causes a whole range of problems related mainly to the organization of effective mixture formation and fuel burnout, as well as to ensuring stable fuel supply. Thus, the cycle dose of injected fuel in idle mode is 8–12 times less than the cycle dose in nominal mode, which determines increased requirements for fuel equipment and difficulties in ensuring high-quality mixture formation. At the same time, diesel engines operate in idle mode up to 50 % of the total operating time, consuming up to 15–20% of the fuel. For truck engines, the relative idle time is approximately 20–25 %. Thus, the development of measures to improve the efficiency of diesel engines at idle is relevant. The purpose is to perform a numerical analysis of the effect of switching off cycles in diesel engines for autotractor and diesel locomotive purposes on the working processes in the cylinder and the indicator parameters of the cycle in idle modes. When writing the article, traditional methods (comparison, description, and measurement), generallogical methods and research techniques (analysis, generalization, etc.) were used. A numerical analysis of the operating cycle of a diesel engine equipped with a cycle shutdown system was performed. The relationship between changes in fuel injection characteristics when cycles are turned off with indicator indicators of the engine operating cycle in idle load modes is disclosed. It has been established that the expediency of switching off cycles in a specific engine operation mode is determined primarily by the features of the injection, carburetion and fuel burnout processes.

Annotation: Main problem: The article analyzes water quality assurance as the main goal of preserving human health. The study of chemical and microbiological parameters of wastewater and drinking water was carried out using generally accepted standards. The number of deaths associated with the use of contaminated drinking water, according to WHO, tripled in 2021 and reached almost 19 thousand against 6 thousand in 2020. In addition, the number of neoplasms, diseases of the genitourinary system, digestive organs and skin increased by 2 %, to 1.486 million. The reasons for the increase in the level of harmful chemicals and microbiological pollutants in the water are outdated sewage treatment plants, old pipes and disinfection with chlorine. Purpose: Study of the quality of wastewater and drinking water in Pavlodar, study of the quality of wastewater and drinking water in Pavlodar. Methods: Sampling of wastewater, chemical and bacteriological analysis of wastewater and drinking water, statistical method, correlation analysis of experimentally obtained results and calculated characteristics, etc. Results and their significance: In the field of public health risk, pollution of reservoirs that are sources of household drinking water supply and recreational water use, the continuing necessary high deterioration of water supply networks, their accident rate, as a result of low level of operation, failures in the operation of treatment facilities. Hygienic assessment of reservoirs according to complex indicators indicates the continuing high degree of water pollution in places of water use. The water quality indicators of the surface reservoirs of the region remain low in terms of sanitary and chemical (primarily organoleptic and general sanitary), as well as microbiological indicators. According to toxicological indicators, the level of water pollution in places of water use is estimated as moderate. The main pollutants of the Irtysh River in Pavlodar are industrial enterprises and housing and communal facilities that discharge untreated or insufficiently treated wastewater into reservoirs. A complex of causes of drinking water pollution has been identified: high deterioration of water supply networks, their accident rate, because of a low level of operation, failures in the operation of treatment facilities, unfair treatment of industrial wastewater by industrial enterprises of Pavlodar, etc. Priority preventive directions for improving the quality of water as a source of life are the implementation of long-term targeted planning of measures for the modernization of water supply and sewerage networks and facilities in Pavlodar. The state of water supply necessary and measures to improve it should be constantly monitored and considered at meetings of sanitary and anti-epidemic commissions.