CONTRIBUTION TO THE STUDY OF THE DISTRIBUTION OF HEAT TRANSFER COEFFICIENTS DURING THE PHASE OF THE WORKING CYCLE OF AN INTERNAL COMBUSTION ENGINE

2019 ◽  
Author(s):  
A. Stambuleanu
Author(s):  
P. Hashchuk ◽  
S. Nikipchuk

Deterministic and, in a certain sense, "linear" interpretation of the world often leads to the recognition of the fact that the more accurate model we need, the more complex it must be (as in case of a formalized reproduction of the real system, or the implementation of the desired system properties in the process of formal synthesis of something new). Instead, following the principle of synergy leads to the conviction that there is always a certain model of optimal complexity e.g. in the synthesis of the new system, and in the analysis of real system peculiarities. However, the model of reality could be a part of this reality that is included to the carefully structured formal description. Since we cannot penetrate into the working space of the serial engine while testing, we should use a test engine of a special construction when the working space corresponds to the laws of similarity and this engine will serve as a model of the working space of the serial engine.     The study illustrates the effectiveness of hard-soft technology while investigating the peculiarities of heat generation and heat consumption in the internal combustion engine, which will combine mathematic and algorithmic means of modelling as well as the means of real simulation. The necessity of hard-soft technology introduction arises from the excessive complexity of thermal phenomena occurring in the internal combustion engine (ICE), and the inability to fully subordinate these phenomena to existing analytical models. The combination of original and analytical properties, reality and virtual reality while modelling the processes in internal combustion engines allows us to substantially improve the quality of information in the process of design and engine construction. Taking this into consideration, there are some natural grounds to apply principles of heuristic self-organization, self-learning, means of the neural networks, etc. in the design implementation. The study demonstrates the example of modelling the real working space of ICE with the forced start that serves as a supplement to the mathematical algorithmic two-zone model of heat generation / heat consumption / heat extraction. The basic information that can be obtained by means of hard-soft technology in the framework of, for example, the two-zone model of the work process in the gasoline engine, is the variability with the change in the angle of rotation of the crankshaft of the engine: absolute pressure (indicative diagram); absolute temperature; heat transmitted inside the cylinder between zones; coefficient of excess air; coefficient of heat transfer; intensity of heat extraction in the process of combustion of fuel; intensity of heat transfer through the walls of the cylinde


Author(s):  
E.T. Plaksina ◽  
A.B. Syritsky ◽  
A.S. Komshin

The article considers the main methods of internal combustion engine diagnostics. A method based on measuring the time intervals between the phases of the working cycle of the mechanism is described. An algorithm for measuring the time intervals from the formulation of the problem to the proof of the efficiency of this method on an internal combustion engine has been determined. The installation of the angle sensor on the crankshaft of the experimental bench engine VAZ 21126 is shown. The basis for the construction of a mathematical model of the crankshaft is presented and the main factors influencing its movement are identified. A criterion has been established according to which the misfire is determined most accurately. The results obtained can be used for developing diagnostic systems for internal combustion engines, as well as engines operating in extreme conditions, for example, beyond the Arctic Circle, on ships, etc.


Author(s):  
David R. Buttsworth ◽  
Abdalla Agrira ◽  
Ray Malpress ◽  
Talal Yusaf

Simulation of internal combustion engine heat transfer using low-dimensional thermodynamic modelling often relies on quasi-steady heat transfer correlations. However, unsteady thermal boundary layer modelling could make a useful contribution because of the inherent unsteadiness of the internal combustion engine environment. Previous formulations of the unsteady energy equations for internal combustion engine thermal boundary layer modelling appear to imply that it is necessary to adopt the restrictive assumption that isentropic processes occur in the gas external to the thermal boundary layer. Such restrictions are not required and we have investigated if unsteady modelling can improve the simulation of crank-resolved heat transfer. A modest degree of success is reported for the present modelling which relies on a constant effective turbulent thermal conductivity. Improvement in the unsteady thermal boundary layer simulations is expected in future when the temporal and spatial variation in effective turbulent conductivity is correctly modelled.


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