Indirect Methods for Diagnosing Cracks in the Internal Combustion Engine Cylinder Head Based on a Comprehensive Analysis of Cooling System Parameters

The study objective is to develop a comprehensive algorithm for indirect diagnosis of cracks in a cylinder head based on a synchronous analysis of the dynamics of absolute pressure in the cooling system and temperature jumps of the coolant with reference to the operating parameters of the internal combustion engine. The task to which the paper is devoted is the verification of a digital signal processing algorithm that makes it possible to automate the detection of malfunctions by revealing weak diagnostic signs against the background of natural noise and vibrations by filtering, differentiating, statistical analysis and synthesis of an integral criterion. Research methods. Forecasting, mathematical modeling, statistical analysis, system analysis, reliability theory, probability theory, management theory. The novelty of the work is in considering the joint factor of synchronous dynamics of absolute pressure and temperature in the cooling system, the complementary signs of a single defect, which makes it possible to increase the reliability of the diagnosis based on the principle of cross-checking. Study results. An improved method for indirect determination of given malfunction is proposed based on a comprehensive analysis of the pressure dynamics in the cooling system and unstable thermal state of the coolant Conclusions. Diagnostic information content of the cooling system parameters (pressure and temperature) increases significantly when analyzing their dynamics (time derivatives) synchronized with the corresponding engine operating modes. The critical zones for the demonstration of the defect are the modes of steady high load and sudden transient accelerations.