EVALUATION OF THE TECHNICAL CONDITION OF A SHIPBOARD INTERNAL COMBUSTION ENGINE IN OPERATING CONDITIONS

Abstract

The article provides a classification of means for diagnosing an internal combustion engine. The methods used to assess the technical condition of engines in operating conditions are considered.

The main failures that occur during the operation of internal combustion engines are analyzed. From the analysis of failures, it was found that failure due to wear and mechanical damage attributable to the cylinder–piston group prevail. It is proved that the consequence of this type of failure is often the absence of ignition in one of the engine cylinders, which causes a disruption of the duty cycle and a significant loss of power in the nominal mode. It is established that power is one of the diagnostic parameters of the state of the engine, which is associated with the torque and angular velocity of the crankshaft, the rotation of which is ensured by the work of expanding the gases in the combustion chamber.

It is concluded that the torque is a diagnostic sign that fully describes the technical condition of the engine, but it is difficult to measure, therefore, it is proposed to use the angular acceleration of the crankshaft as an estimated diagnostic indicator to determine the technical condition of the internal combustion engine. Since the angular acceleration of the crankshaft is a function of increasing the angular velocity, the nature of the change in angular acceleration can be a measure of the torque of the engine, and therefore the technical condition.

The use of angular acceleration as a diagnostic indicator for a collapsible, without a load assessment of the technical condition of an internal combustion engine under operating conditions is theoretically justified and confirmed. The result of determining the technical condition of a marine engine is a graph of the dependence of the magnitude of the angular acceleration on the angle of rotation of the crankshaft of all engine cylinders, allowing using the express evaluation of the extrema of the angular acceleration, the midline of the angular acceleration to determine the presence of a faulty cylinder and the entire engine as a whole.