The article is devoted to determinе the parameters of the equivalent torsional scheme of the crankshaft of automotive internal combustion engines. The parameters that depend on the design features of the studied engines include the number and moments of inertia of the motor masses, the stiffness of the shaft sections and their length. Currently used methods are based on empirical data and require their identification for each specific model of the engine under study. To improve the adequacy of the data obtained, it is necessary to conduct fullscale tests of the crankshafts for stiffness. Modeling the spatial structure of the crankshaft by finite elements with further determination of the studied parameters, although it facilitates the task, requires subsequent mandatory verification of the model used. To unify the calculation methods and reduce their complexity, it is proposed to consider the elastic-deformable section of the crankshaft, taking into account the geometric parameters. The accuracy of the results obtained depends on the curve equations describing the elastic deformation surface of the crankshaft transition sections. A preliminary evaluation of the crankshaft parameters can be performed on a piecewise linear surface. Reducing the sampling step increases the accuracy of the results. In the same way, we can take into account such design parameters of the crankshaft as the overlap of the necks, the presence of cavities inside the main and connecting rod necks. The proposed method can be used for automate crankshaft calculations of modern automotive internal combustion engines.
An integrated approach was applied for production enhancement of the upper and lower shaly sandstone reservoirs of the Ignalinsky and Tympuchikansky fields in the Leno-Tunguska oil and gas province of the East Siberian Basin, Russia. The approach includes both comprehensive laboratory studies and a direct strategy of hydraulic fracturing design, as well as solutions to obtain optimum well performance. The approach can be implemented in future prospects and can form part of the strategy for future development in the region. Extensive laboratory research was performed to select the proper fluid for proppant transport that could withstand all the complicated terrigenous conditions within the fields. One of the main challenges was rheological suitability of the fluid at low reservoir temperatures. The laboratory studies were important for identifying the best fluid for fast fracture cleanup while optimizing the sand-carrying capacity of the fracturing fluid. The hydraulic fracturing design incorporated calibrated petrophysical and geomechanical analysis with actual fluid rheology characterization taken from laboratory test results. The laboratory work confirmed that the reservoir rock was water sensitive, with a significant presence of clay minerals including kaolinite, montmorillonite, and montmorillonite mixed with illite. A new generation of clay stabilizer was used to address this sensitivity. In addition, an enzyme breaker was used with the objective of effectively breaking the fracturing fluid at low reservoir temperatures. The fracturing operations that were performed during two winter campaigns resulted in high starting and operating production rates. The treatment designs incorporated a linear gel pre-pad stage prior to the crosslinked pad stage in an effort to extend fracture half-length while reducing the risk of the fracture growing in height into overlying gas-saturated layers. The results of the design efforts were analyzed using logging and fracture treatment data, which demonstrated that the design was effective in avoiding the gas-saturated formation. Overall, 23 hydraulic fracturing operations were done in five wells at Ignalinsky and Tympuchikansky fields for the B10 and B13 formations. Production results were analyzed, and further optimization paths were identified. The study breaks new ground in enhancing the hydrocarbon extraction from low-temperature shaly sandstones with mixed wettability, not just with terrigenous reservoirs within the above-mentioned fields, but also with other reservoirs of a similar geological context, primarily the Leno-Tunguska oil and gas province of the East Siberian Basin, Russia. This is especially important in view of the depletion of oil reserves in Western Siberia and the growing interest in the development of hydrocarbon fields in Eastern Siberia.
Increasing the efficiency of modern internal combustion engines is going in the direction of optimizing the gas distribution phases in order to adjust them to the operating conditions of motor vehicles. Hyundai has announced the development of the first production engine with continuously variable valve operation time – Continuously Variable Valve Duration. (Research purpose) The research purpose is in conducting a kinematic analysis of the gas distribution mechanism with an adjustable valve operating time, identifying the theoretical possibilities of this mechanism in comparison with the information provided in the prospects. (Materials and methods) The methods of kinematic analysis of lever mechanisms were used in the work. (Results and discussion) The analysis of the design of the gas distribution mechanism with an adjustable valve operating time made it possible to choose a suitable structural scheme that is equivalent to the original mechanism. The article presents the most effective method of kinematic analysis of this mechanism and developed on its basis a program for calculating the angles of rotation of the cam and the shaft of the gas distribution mechanism. (Conclusions) An engine with a valve operating time control system allows you to more effectively adjust the cylinder filling depending on the operating conditions due to the variable phase of rotation of the camshaft. The valve timing control system offered by Hyundai should only work with the valve timing control mechanism, since when the cam rotation speed changes, it starts working in the wrong phase that should be at a given time. With a slow rotation of the cam, it lags behind in phase from the shaft of the gas distribution mechanism, and with a fast rotation of the cam, on the contrary, the phase advance of the shaft of the gas distribution mechanism occurs.
The article is devoted to assessing the influence of the parameters of car transmission elements on the nature of the resulting torsional vibrations of the crankshaft of its power plant. As a rule, at present, the study of torsional vibrations of the crankshafts of piston internal combustion engines is carried out separately from the conditions of their operation. Only the operating modes of the engines, the torques of individual cylinders are considered, taking into account the order of operation and the angle between the flashes. If necessary, instead of a linear equivalent torsional circuit, branched circuits are considered that take into account the influence of individual engine mechanisms. Perturbing moments in such schemes occur only on the crank of the crankshaft. Only engine operating modes are considered, which take into account the elements of the car transmission and their influence on the nature of torsional vibrations along the entire length of the driven shaft. The moments of inertia of each transmission element and the stiffness of the equivalent torsional circuit sections are determined. The oscillation equations of the equivalent design scheme are drawn up taking into account the transmission elements. The values of the natural oscillation frequencies are determined by solution of homogeneous differential equations. The influence of the external environment can be estimated by applying perturbing the moment per equivalent mass replacing elements of the undercarriage of the car. Given the large values of the moments of inertia of the elements of transmission and the frequency range of their own vibrations, it is possible to explain the displacement of the amplitude of vibrations and their nodes. The considered technique is of interest for scientific and technical workers, and designers involved in the design of transmission elements for motor vehicles.
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