Repeatability of High-Pressure Measurement in a Diesel Engine Test Bed

Abstract

This paper addresses the issue of metrological accuracy of instantaneous in-cylinder pressure measurement in a diesel engine test bed. In studies, the central unit has been the single-cylinder AVL 5402 engine. The pressure measurement was performed with a sensor designed for thermodynamic analysis, and the results were related to the crank angle, where two rotations corresponding to the four-stroke working cycle were denoted as angles between −360° and +360°. The novelty of this paper is the proposition of how to perform a type A uncertainty estimation of the in-cylinder pressure measurement and to assess its repeatability. It was demonstrated that repeatability of the measurement during the ignition process was difficult to estimate because of the phenomena that cannot ensure the repeatability conditions. To solve the problem, two methods were proposed. In one method, the pressure was measured in the subsequent cycles immediately after the ignition was turned off, and in another method, the engine was driven by a starter. The latter method provided maximal pressure values much lower than during usual tests. The obtained repeatability of measured pressure was %EV = 0.4%, which proved high capability of the evaluated measurement system.

Tribological Assessment of Aluminum Cylinder Material for Piston Compressors in Trucks and Buses Brake Systems

“…The mechanical characterization of the material and the determination of the mechanical properties of the surface layer were performed using CSM Nano Hardness Tester (NHT 2 ), with Berkowich diamond indenter [10,20].…”

“…The set goals could be achieved by applying modern technologies in order to optimize combustion and tribological processes [4][5][6][7][8][9][10].…”

“…According to the above, main focus during optimization of internal combustion engines (ICE) is friction reduction, resulting in lower fuel consumption and exhaust emission [10][11][12].…”

“…Then, tribology research in domain of ICE and piston compressors designed from lightweight materials was also performed [10].…”

Study of the Effect of Physicochemical Degradation and Contamination of Motor Oils on Their Lubricity

“…Lubrication of the internal combustion engine is essential to reduce unwanted energy and material losses, i.e., to increase its fuel efficiency and service life [7][8][9]. From this point of view, two types of additives are essential that are mixed into the lubricating motor oil; these are friction modifiers and anti-wear additives [10].…”