DEVELOPMENT OF KNOCK MATHEMATICAL MODEL FOR MODERN IC ENGINE

Abstract

The paper examines under-studied aspects of internal combustion engine management, such as the use of knock. In knock, instead of a constant frontal flame, a detonation wave is formed in the combustion zone, carrying at supersonic speed. Fuel and oxidant are detonated in compression wave. This process, from the point of view of thermodynamics, increases the efficiency of the engine. In internal combustion engines, there are two different modes of combustion propagation of air mixture fuel: deflagration and detonation. Engines operating in detonation combustion mode are currently not used and their capabilities are most interesting. Modern internal combustion engines do not carry the detonation mode well, but the possibility of short-term combustion of part of the fuel-air mixture with detonation is embedded in their design. The situation of detonation is currently constantly being studied, it is considered as a harmful component of the combustion process, which requires improvement of the engine, its control and use of modern fuel. It is proposed to use this, considered random, process to increase the torque and power of the internal combustion engine. The possibility of using detonation combustion of fuel-air mixture in internal combustion engine as a useful part of the working process is considered, and the possibility of controlling combustion of fuel-air mixture in a mixed mode is assumed, which allows to improve indicator parameters. Assumptions have been made to create a model and the cylinder pressure has been simulated during the combustion phase of the partially detonated fuel-air mixture. The method of heat generation calculation has been determined, which is one of the most important stages of mathematical model creation, as this determines accuracy and adequacy of calculated parameters, both for deflagration combustion modes of fuel-air mixture and using detonation combustion. Proposed procedure for calculation of internal combustion engine operating cycle parameters makes it possible to carry out real-time calculations and account for influence of binary fuel composition on parameters of power, economy, mechanical and dynamic load on parts of crank mechanism, as well as thermal load on engine.