Molodan A. Estimation of technical state of the piston-cylinder-unit of the engine with account of blow by gas flow separation

The object of investigation is the processes of crankcase blow-by gases in the internal combustion engine depending on the technical state change of piston-cylinder-unit coupling and the valve gear affecting the engine life. The subject of investigation is the affect of stream splitting of gases penetrating into the engine's crankcase from the head-end on the accuracy of piston-cylinder-unit technical state and valve gear assessment. The author has applied the methods of mathematical statistics, reliability theory, simulation modeling of complex systems and optimization problems solving. The scientific novelty of the given paper lies in the fact that for the first time there has been determined the ratio between the speed of gas outflow and its quantity penetrating through the head-end and PCU into the engine's crankcase that allowed for the first time to develop the method of PCU technical state assessment method taking into account the stream splitting of gases penetrating into the crankcase and increasing the assessment accuracy. The limiting and admissible diagnostic parameters of gases penetrating into the engine's crankcase through the clearance areas in PCU and valve gear of repaired engines have been determined for the first time. The practical value of the results obtained include quality control accuracy increase in the process of capital repair by 15-40 %, the development of PCU and valve gear diagnostic parameters standards, increase of driver's informativeness by means of on-board IMS improvement of crankcase blow-by gases limiting value in engines equipped with the warning system. The main propositions of the given thesis are implemented at auto repair plants № 110 and № 126 in Kharkiv, at auto repair plant in Dobropolye, Donetsk Region, Ukraine, and also adopted for further application by diagnostic laboratory and technical maintenance of National Scientific Center " Institute of Mechanization and Electrification of Agriculture" of Ukrainian Academy of Agrarian Sciences. The field of application: enterprises that carry out technical maintenance and capital repair of automobile engines and laboratories of automobile and tractor engines technical maintenance and diagnosing.