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The wear of cylinder kit components of internal combustion engine leads to the increase in blowby and oil consumption and usually determines engine lifetime. Due to the reduced development time, efficient methods for predictive evaluation of engine life are necessary. The paper presents a method of engine lifetime prediction, which takes advantage of the results of test bench engine investigations as well as the results of simulations carried out with the use of the ring pack model of the engine. Ring pack simulations are used for the determination of the boundary wear at which the effectiveness of the pack drops to the permissible level. On the basis of the test bench investigations, the course of engine wear is established. Lifetime is estimated by extrapolating the wear course to the boundary value. The results of example calculations for automotive diesel engine are presented.

The paper presents a comparative analysis of the operational parameters, smoke emission and the content of toxic components in exhaust gases of a compression ignition engine fuelled with fossil diesel, commercially available biodiesel (fatty acid methyl ester) and their 50%/50% blend. The study was carried out using a diesel engine equipped with an in-line injection pump used in delivery vans. An indirect injection, considerably worn engine was chosen because such engines are very often fuelled with the less expensive biodiesel. Measurements were made on an engine operated at different rotational speeds under full load as well as using the European Stationary Cycle (ESC) test. Emissions of regulated and non-regulated compounds were measured with the use of the Fourier-Transform Infrared (FTIR) analytical system, which provided concentrations of 23 exhaust gas components.

The paper investigates the cylinder liner wear and its influence on the engine blowby. The course of cylinder liner wear was established on the basis of investigation, which was carried out using 5 diesel engines during long-lasting operation in motor trucks. Cylinder diameters were periodically measured in two perpendicular planes at four depths of the liner. During service of the trucks the blowby rate was also measured, which enabled evaluating of the changes of the blowby rate as a function of truck mileage. The effect of cylinder wear on the blowby was also predicted with the use of a mathematical model of a gas flow through the ring pack. The results of the numerical simulations and empirical investigations are compared and discussed.

The paper considers the effect of axial and radial clearances of compression rings in the piston grooves on the engine blowby. A mathematical model of piston-rings-cylinder seal, which integrates model of gas flow through the crevices of the RPC seal and model of rings motions in the grooves was used to predict the influence of particular clearances values on the blowby. The results of numerical calculations show that this influence is different for the top and second ring clearances and depends on engine operating conditions (especially rotational speed). The paper also presents some results of experimental research conducted to verify the model. The results of the experiment confirmed the results of the numerical predictions.