Premature engine failures of KamAZ vehicles with common rail fuel supply system in real operation

Introduction. For the manufacturer and consumer enterprises of the products, it is of interest to know the real operational reliability of power units of KamAZ vehicles, their weakest points, the causes of premature failures, as well as methods for identifying and preventing their occurrence, and therefore carry out scientific research aimed at solving the above task is relevant and timely. Methods. The study of the reliability of systems, components and assemblies of engines of KamAZ vehicles was carried out in the conditions of the official dealership center “Technical center Severny” (Irkutsk), specializing in the sale, maintenance and repair of KamAZ vehicles during 2020–2024. the study involved KamAZ vehicles with 740 engine, including those under warranty. The automobiles with these power units were operated primarily in the Irkutsk region, including server regions. at the same time, each work order recorded the reason for contacting the service, the mileage of the car, as well as the types of work performed. An important step was to identify the distribution law of the most frequent failures of engine systems and components. Discussion and conclusion. The analysis of the data obtained during the study indicates the predominance of two types of premature failures – cylinder heads, as well as fuel supply systems, primarily electrohydraulic injectors. It was found that premature failures of cylinder head and electrohydraulic injectors obey the Weibull distribution law and have mathematical expectations of a failure time of 49.6 thousand km for injectors and 41.9 thousand km for cylinder heads. At the same time, the failures of the cylinder head of the highly accelerated engines of the KamAZ-740.7 family (with a capacity of over 360 hp) are caused by increased thermal stress and can be classified as structural and operational.