Multi-criteria durability assessment of a CI internal combustion engine engine durability, forecasting, operational testing

The article presents an assessment of the durability of a compression-ignition engine using technical, economic, and oil-based criteria. The reliability of the conducted forecast was evaluated, and the optimal method for forecasting the durability of a CI engine was identified.1. INTRODUCTION
In the theory of machine operation, durability is defined as the ability to maintain a state of fitness under specified operating conditions. A state of fitness is a state of an object that guarantees the full realization of its intended functional tasks. The given definition describes durability in a descriptive sense, whereas in a quantitative (normative) sense, the durability of an object is the generalized operating time (calculated from the moment of manufacture) during which the object maintains selected characteristics within specified limits [1]. The choice of these characteristics, and consequently their limit values, is determined by the adopted criteria for assessing durability. It is also said that durability in a quantitative sense is the generalized operating time until the object reaches a limit state.
From the presented definitions, it follows that in the issues of durability of technical objects, including internal combustion engines, there are two main groups of problems: the selection of durability indicators for the object, and the criteria for assessing the limit state of the object.
Regarding the first group, the literature on the subject sometimes distinguishes two groups of indicators for the durability of vehicles and their components [2]: control indicators – used in bench tests or experimental model tests, and operational indicators.
The first group includes the number of operating hours or the amount of work performed under conventional test conditions until the object reaches limit wear or damage.
The second group of indicators includes operating time in hours, mileage in kilometers, and the amount of work performed until failure under normal operating conditions. (…)

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